首先下載外掛ZXing，連結在下面。解壓後把unity資料夾的檔案匯入unity中。

連結：https://pan.baidu.com/s/1_En2Tc2kdiDw8fvvzJZKYQ
提取碼：vl5k

程式碼如下：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using ZXing;
using ZXing.QrCode;

public class QRCodeManager
{
    /// <summary>
    /// 直接返回圖片
    /// </summary>
 

    /// <param name="textForEncoding"></param>
    /// <param name="width"></param>
    /// <param name="height"></param>
    /// <param name="margin"></param>
    /// <returns></returns>
    public Texture2D GetTexture2D(string textForEncoding, int width, int
 
 height, int margin)
    {
        if (textForEncoding == "")
        {
            Debug.Log("錯誤！資料不能為空字串！");
            return null;
        }
        Texture2D t2d = new Texture2D(width, height);
        t2d.SetPixels32(GetQRcode(textForEncoding, width, height, margin));
        t2d.Apply();
        
 
return t2d;
    }
    /// <summary>
    /// 只返回生成二維碼的顏色資料
    /// </summary>
    /// <param name="textForEncoding"></param>
    /// <param name="width"></param>
    /// <param name="height"></param>
    /// <returns></returns>
    public Color32[] GetQRcode(string textForEncoding, int width, int height, int margin)
    {
        if (textForEncoding == "")
        {
            Debug.Log("錯誤！資料不能為空字串！");
            return null;
        }
        BarcodeWriter writer = new BarcodeWriter  //設定二維碼變數類
        {
            Format = BarcodeFormat.QR_CODE,  //設定二維碼格式
            Options = new QrCodeEncodingOptions //設定編碼格式
            {
                CharacterSet = "UTF-8",// 設定中文模式
                Height = height, //設定寬高
                Width = width,
                Margin = margin  //設定二維碼的邊距
            }
        };
        return writer.Write(textForEncoding);
    }
    public ZXing.Result CheckQRCode(Texture2D t2d)
    {
        if (t2d == null)
        {
            Debug.Log("錯誤！圖片為空！");
            return null;
        }
        Color32[] colorDatas = t2d.GetPixels32();
        BarcodeReader m_barcodeRender = new BarcodeReader();
        return m_barcodeRender.Decode(colorDatas, t2d.width, t2d.height);//將畫面中的二維碼資訊檢索出來
    }
}