diff --git a/src/util/generatechaptcha.lua b/src/util/generatechaptcha.lua
new file mode 100644
index 0000000..97e2585
--- /dev/null
+++ b/src/util/generatechaptcha.lua
@@ -0,0 +1,72 @@
+---
+--- Generated by EmmyLua(https://github.com/EmmyLua)
+--- Created by admin.
+--- DateTime: 2025/11/19 20:18
+--- 生成校验码图片
+
+--设置随机种子
+local resty_uuid = require("resty.uuid")
+math.randomseed(tonumber(resty_uuid.gennum20()))
+
+--在32个备选字符中随机筛选4个作为captcha字符串
+local dict={'A','B','C','D','E','F','G','H','J','K','L','M','N','P','Q','R','S','T','U','V','W','X','Y','Z','2','3','4','5','6','7','8','9'}
+local stringmark = ""
+for i = 1, 4 do
+    stringmark = stringmark..dict[math.random(1,32)]
+end
+
+--图片基本info
+--picgid
+local filename = "1"..resty_uuid.gen20()..".png"
+--图片78x26
+local xsize = 78
+local ysize = 26
+--字体大小
+local wsize = 17.5
+--干扰线(yes/no)
+local line = "yes"
+
+--加载模块
+local gd = require('gd')
+--创建面板
+local im = gd.createTrueColor(xsize, ysize)
+--定义颜色
+local black = im:colorAllocate(0, 0, 0)
+local grey = im:colorAllocate(202, 202, 202)
+local color = {}
+for c = 1, 100 do
+    color[c] = im:colorAllocate(math.random(100), math.random(100), math.random(100))
+end
+--画背景
+x, y = im:sizeXY()
+im:filledRectangle(0, 0, x, y, grey)
+--画字符
+gd.useFontConfig(true)
+for i = 1, 4 do
+    k = (i - 1) * 16 + 3
+    im:stringFT(color[math.random(100)], "Arial:bold", wsize, math.rad(math.random(-10,10)), k, 22, string.sub(stringmark, i, i))
+end
+--干扰线点
+if line == "yes" then
+    for j = 1, math.random(3) do
+        im:line(math.random(xsize), math.random(ysize), math.random(xsize), math.random(ysize), color[math.random(100)])
+    end
+    for p = 1, 20 do
+        im:setPixel(math.random(xsize), math.random(ysize), color[math.random(100)])
+    end
+end
+--流输出
+local fp = im:pngStr(75)
+
+--redis中添加picgid为key,string为value的记录
+--setRedis(filename, stringmark)
+
+--response header中传参picgid
+ngx.header.content_type = "text/plain"
+ngx.header.picgid = filename
+
+--页面返回pic
+ngx.say(fp)
+
+--nginx退出
+ngx.exit(200)