procedure TForm1.Button1Click(Sender: TObject);

var

  Dir, FileTitle, FileExt: string;

  s,s1: string;

  j:Integer;

begin

  Dir := 'C:\';

  FileTitle := '新建 文本文档';

  FileExt := '.txt';

  s1:=Dir+FileTitle+FileExt;

  j:=;

  if FileExists(s1)  then  //C:\新建 文本文档.txt

  begin

    s:=Format('%s%s(%d)%s', [dir, FileTitle, j, FileExt]);

    while FileExists(s) do

    begin

        Inc(j);

        s := Format('%s%s(%d)%s', [dir, FileTitle, j, FileExt]);

    end;

    if not FileExists(s) then Memo1.Lines.SaveToFile(s);

    end

  else

     Memo1.Lines.SaveToFile(s1);

end;