diff --git a/ExtraIsland/Components/ProfileInformation/ProfileInformation.axaml.cs b/ExtraIsland/Components/ProfileInformation/ProfileInformation.axaml.cs
index 5144e7d..056536d 100644
--- a/ExtraIsland/Components/ProfileInformation/ProfileInformation.axaml.cs
+++ b/ExtraIsland/Components/ProfileInformation/ProfileInformation.axaml.cs
@@ -55,14 +55,11 @@ void LessonsServiceOnPostMainTimerTicked(object? sender,EventArgs e) {
     int GetWeekInSemester(DateTime? current = null) {
         current ??= _exactTimeService.GetCurrentLocalDateTime();
         DateTime orientation = (DateTime)((dynamic)AppBase.Current).Settings.SingleWeekStartTime;
-        int oriWeek = orientation.DayOfWeek == DayOfWeek.Sunday ? 6 : Convert.ToInt32(orientation.DayOfWeek) - 1;
-        
-        //regulate
-        DateTime startMonday = orientation.AddDays(-oriWeek);
-        int lastDelta = current.Value.DayOfWeek != DayOfWeek.Sunday ? 7 - Convert.ToInt32(current.Value.DayOfWeek) : 0;
-        DateTime lastEnd = current.Value.AddDays(lastDelta);
-        
-        TimeSpan totalWeekDelta = lastEnd - startMonday;
+        int daysToStartOfWeek = ((int)orientation.DayOfWeek - (int)Settings.FirstDayOfWeek + 7) % 7;
+        DateTime startDay = orientation.AddDays(-daysToStartOfWeek);
+        int daysToEndOfWeek = ((int)Settings.FirstDayOfWeek - (int)current.Value.DayOfWeek + 6) % 7;
+        DateTime lastEnd = current.Value.AddDays(daysToEndOfWeek);
+        TimeSpan totalWeekDelta = lastEnd - startDay;
         return Convert.ToInt32(totalWeekDelta.Days + 1) / 7;
     }
 }
\ No newline at end of file
diff --git a/ExtraIsland/Components/ProfileInformation/ProfileInformationConfig.cs b/ExtraIsland/Components/ProfileInformation/ProfileInformationConfig.cs
index c44af52..a315021 100644
--- a/ExtraIsland/Components/ProfileInformation/ProfileInformationConfig.cs
+++ b/ExtraIsland/Components/ProfileInformation/ProfileInformationConfig.cs
@@ -10,6 +10,9 @@ public partial class ProfileInformationConfig : ObservableObject {
     
     [ObservableProperty]
     bool _isShortModeEnabled;
+    
+    [ObservableProperty]
+    DayOfWeek _firstDayOfWeek = DayOfWeek.Monday;
 }
 
 public enum ProfileInformationType {
diff --git a/ExtraIsland/Components/ProfileInformation/ProfileInformationSettings.axaml b/ExtraIsland/Components/ProfileInformation/ProfileInformationSettings.axaml
index 14f7799..0426330 100644
--- a/ExtraIsland/Components/ProfileInformation/ProfileInformationSettings.axaml
+++ b/ExtraIsland/Components/ProfileInformation/ProfileInformationSettings.axaml
@@ -8,6 +8,7 @@
                   x:TypeArguments="components:ProfileInformationConfig">
     <ci:ComponentBase.Resources>
         <converters:EnumDescriptionConverter x:Key="EnumDescriptionConverter" />
+        <converters:DayOfWeekEnumFullStringConverter x:Key="DayOfWeekEnumFullStringConverter"/>
     </ci:ComponentBase.Resources>
     <ScrollViewer
         DataContext="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=components:ProfileInformationSettings}}">
@@ -35,6 +36,22 @@
                     <ToggleSwitch IsChecked="{Binding Settings.IsShortModeEnabled, Mode=TwoWay}"/>
                 </controls:SettingsExpander.Footer>
             </controls:SettingsExpander>
+            <controls:SettingsExpander IconSource="{ci:FluentIconSource &#xE310;}"
+                                       Header="每周第一天"
+                                       Description="设置每周的第一天是周几">
+                <controls:SettingsExpander.Footer>
+                    <ComboBox
+                        MinWidth="20"
+                        SelectedItem="{Binding Settings.FirstDayOfWeek, Mode=TwoWay}"
+                        ItemsSource="{Binding FirstDayOfWeekOptions}">
+                        <ComboBox.ItemTemplate>
+                            <DataTemplate>
+                                <TextBlock Text="{Binding Converter={StaticResource DayOfWeekEnumFullStringConverter}}" />
+                            </DataTemplate>
+                        </ComboBox.ItemTemplate>
+                    </ComboBox>
+                </controls:SettingsExpander.Footer>
+            </controls:SettingsExpander>
             <Label HorizontalAlignment="Center" 
                    Foreground="{DynamicResource MaterialDesignBodyLight}">
                 Added by ExtraIsland
diff --git a/ExtraIsland/Components/ProfileInformation/ProfileInformationSettings.axaml.cs b/ExtraIsland/Components/ProfileInformation/ProfileInformationSettings.axaml.cs
index 115692b..f69559b 100644
--- a/ExtraIsland/Components/ProfileInformation/ProfileInformationSettings.axaml.cs
+++ b/ExtraIsland/Components/ProfileInformation/ProfileInformationSettings.axaml.cs
@@ -11,4 +11,14 @@ public ProfileInformationSettings() {
         ProfileInformationType.WeekOfSemester,
         ProfileInformationType.ParityOfWeek
     ];
+
+    public List<DayOfWeek> FirstDayOfWeekOptions { get; } = [
+        DayOfWeek.Sunday,
+        DayOfWeek.Monday,
+        DayOfWeek.Tuesday,
+        DayOfWeek.Wednesday,
+        DayOfWeek.Thursday,
+        DayOfWeek.Friday,
+        DayOfWeek.Saturday
+    ];
 }
\ No newline at end of file
diff --git a/ExtraIsland/Shared/Converters/Converters.cs b/ExtraIsland/Shared/Converters/Converters.cs
index d9a4a0c..1745333 100644
--- a/ExtraIsland/Shared/Converters/Converters.cs
+++ b/ExtraIsland/Shared/Converters/Converters.cs
@@ -75,6 +75,27 @@ static string GetEnumDescription(Enum? enumObj) {
     }
 }
 
+public class DayOfWeekEnumFullStringConverter : IValueConverter {
+    object IValueConverter.Convert(object? value,Type targetType,object? parameter,CultureInfo culture) {
+        DayOfWeek day = (DayOfWeek)value!;
+        string description = day switch {
+            DayOfWeek.Sunday => "周日",
+            DayOfWeek.Monday => "周一",
+            DayOfWeek.Tuesday => "周二",
+            DayOfWeek.Wednesday => "周三",
+            DayOfWeek.Thursday => "周四",
+            DayOfWeek.Friday => "周五",
+            DayOfWeek.Saturday => "周六",
+            _ => "???"
+        };
+        return description;
+    }
+
+    object IValueConverter.ConvertBack(object? value,Type targetType,object? parameter,CultureInfo culture) {
+        return string.Empty;
+    }
+}
+
 public class DayOfWeekEnumStringConverter : IValueConverter {
     object IValueConverter.Convert(object? value,Type targetType,object? parameter,CultureInfo culture) {
         DayOfWeek day = (DayOfWeek)value!;