感谢kyra和li913,我才用了kyra的方案，再次感谢

fortran标准没有判断文件夹的功能，你可以直接open该文件夹中一个文件 open(10,file='2003336\data.txt',iostat=i,iomsg=msg) ,配合iostat 和 iomsg就知道是否存在文件夹。

[Fortran] 纯文本查看 复制代码

program main
character elname1*4, elname2*8, folder_name*15,filename*20
integer istat,istat2
real a
write(elname1, '(i4)') 200
write(elname2, '(i8)') 3336
folder_name=trim(adjustl(elname1))//trim(adjustl(elname2))    
inquire(file=trim(folder_name), exist=istat)                                 
write(*,*)istat
if (istat) then
   print*, 'the file exist'
else
   print*, 'the file no exist and will be created'
   istat2=system( "Md "//trim(folder_name)) 
end if 
istat2=CHDIR(trim(folder_name)) !改变当前目录到到文件夹
filename='data.txt' !打开写入数据的txt文件
open(308,file=filename,status='replace',form='formatted')
write(308,*) 500
close(308)
end program main

你用intel fortran的话，可以用
Inquire(DIRECTORY="2003336",exist=b)