uses ComObj;    procedure TForm1.Button1Click(Sender: TObject);
var
  aExcel: Variant;
  I: Integer;
  aFindSheet: Boolean;
begin
  aFindSheet := False;
  aExcel := CreateOleOBject('Excel.Application');
  aExcel.WorkBooks.Add;
  aExcel.Visible := False;
  for I := 1 to aExcel.WorkBooks[1].WorkSheets.Count do
    if aExcel.WorkBooks[1].WorkSheets[I].Name = 'Sheet2' then
    begin
      aFindSheet := True;
      Break;
    end;
    if aFindSheet then
      ShowMessage('Sheet2存在!')
    else
      ShowMessage('Sheet2不存在!');
  aExcel.Quit;
end;