diff --git a/phonedata.js b/phonedata.js
new file mode 100644
index 0000000..e8ef10c
--- /dev/null
+++ b/phonedata.js
@@ -0,0 +1,33 @@
+const fs = require('fs')
+const ops = {1: '移动', 2: '联通', 3: '电信', 4: '电信虚拟运营商', 5: '联通虚拟运营商', 6: '移动虚拟运营商'}
+
+const init = module.exports = (db) => {
+  const buf = fs.readFileSync(db || __dirname + '/phone.dat')
+  const start = buf.readUInt32LE(4)
+  const total = (buf.length - start) / 9 
+
+  const format = (m) => {
+    let idx = buf.readUInt32LE(m * 9 + start + 4)
+    const type = buf.readUInt8(m * 9 + start + 8, 1)
+    let i = idx;
+    for (; buf.readInt8(i) !== 0; i++ ) {}
+    const [province, city, postcode, telcode] = buf.toString('utf8', idx, i).split('|')
+    return { province, city, postcode, telcode, operator: ops[type]}
+  }
+
+  return (no) => {
+    if (no.length < 7) throw new Error('mobile phone number length is 7 at least')
+    const mobile = no.substr(0, 7) 
+    let right = total
+    let left = 0
+    let i = 0
+    while (left < right - 1) {
+      const m = left + parseInt((right - left) / 2) 
+      const x = buf.readUInt32LE(m * 9 + start)
+      if (x > mobile) right = m 
+      else if (x < mobile) left = m 
+      else return format(m)
+    }
+    throw new Error('Not Found')
+  }
+}
diff --git a/phonedata_test.js b/phonedata_test.js
new file mode 100644
index 0000000..2123d07
--- /dev/null
+++ b/phonedata_test.js
@@ -0,0 +1,2 @@
+const find = require('./phonedata')('./phone.dat')
+console.log(find('18201632965'))