国外站点找到的，你可以参考一下。    // formating a floppy drive, harddisk, or another drive
// Eine Diskette, Harddisk oder ein anderes Laufwerk formatieren    {
  The SHFormatDrive API provides access to the Shell's format
  dialog box. This allows applications that want to format disks to bring
  up the same dialog box that the Shell uses for disk formatting.
}    const 
  SHFMT_DRV_A = 0;//磁盘A
  SHFMT_DRV_B = 1;//磁盘B
  SHFMT_DRV_C = 2;//磁盘C ... 依此类推
  SHFMT_ID_DEFAULT = $FFFF;
  SHFMT_OPT_QUICKFORMAT = 0;
  SHFMT_OPT_FULLFORMAT = 1;
  SHFMT_OPT_SYSONLY = 2;
  SHFMT_ERROR = -1;
  SHFMT_CANCEL = -2;
  SHFMT_NOFORMAT = -3;    //声明API函数
function SHFormatDrive(hWnd: HWND;
  Drive: Word;
  fmtID: Word;
  Options: Word): Longint
  stdcall; external 'Shell32.dll' Name 'SHFormatDrive';    procedure TForm1.Button1Click(Sender: TObject);
var
  FmtRes: Longint;
begin
  try
    //格式化A盘，改成SHFMT_DRV_C即格式化C盘了
    FmtRes := ShFormatDrive(Handle,
      SHFMT_DRV_A,
      SHFMT_ID_DEFAULT,
      SHFMT_OPT_QUICKFORMAT);
    case FmtRes of
      SHFMT_ERROR: ShowMessage('Error formatting the drive');
      SHFMT_CANCEL: ShowMessage('User canceled formatting the drive');
      SHFMT_NOFORMAT: ShowMessage('No Format')
        else
          ShowMessage('Disk has been formatted!');
    end;
  except
    ShowMessage('Error Occured!');
  end;
end;    {
  Normally, if a diskette is not in the drive when SHFormatDrive is called,
  the system displays a critical error dialog box that asks the user
  to Abort, Retry, or Ignore.
  You can prevent the system from displaying this dialog box by calling
  the SetErrorMode API with SEM_FAILCRITICALERRORS.
}    //如果磁盘未准备就绪，调用SHFormatDrive时系统会提示错误，你可以在调用SHFormatDrive前用SetErrorMode设置系统错误模式为SEM_FAILCRITICALERRORS，这样系统就不会弹出报错了。    var
  EMode: Word;
begin
  EMode := SetErrorMode(SEM_FAILCRITICALERRORS);
  // ShFormatDrive Code....
  SetErrorMode(EMode);
end;