Finally I found the solution, thanks all!
TCHAR szText[10];
char tmpStr[10] = {'\0'};
int tmp_point_num = 10;
sprintf(tmpStr, "%d", tmp_point_num);
size_t newsize = strlen(tmpStr) + 1;
wchar_t * wcstring = new wchar_t[newsize];
size_t convertedChars = 0;
mbstowcs_s(&convertedChars, wcstring, newsize, tmpStr, _TRUNCATE);
of course, we need include
<pre>#include <string>
#include "atlbase.h"
#include "atlstr.h"
#include "comutil.h"