uses 
  ComObj; 

function ExcelSaveAsText(ExcelFile, TextFile: TFileName): Boolean; 
const 
  xlText = -4158; 
var 
  ExcelApp: OleVariant; 
  vTemp1, vTemp2, vTemp3: OLEVariant; 
begin 
  Result := False; 
  try 
    ExcelApp := CreateOleObject('Excel.Application'); 
  except 
    // Fehler beim цffnen von Excel... 
    // Error occured... 
    Exit; 
  end; 
  try 
    ExcelApp.Workbooks.Open(ExcelFile); 
    ExcelApp.DisplayAlerts := False; 
    vTemp3 := False; 
    vTemp2 := xlText; 
    vTemp1 := TextFile;
    ExcelApp.ActiveWorkbook.SaveAs(vTemp1, vTemp2, vTemp3); 
    Result := True; 
  finally 
    ExcelApp.Quit; 
    ExcelApp := Unassigned; 
  end; 
end; 

procedure TForm1.Button1Click(Sender: TObject); 
begin 
  ExcelSaveAsText('C:\YouExcelFile.xls','C:\YourTextFile.txt'); 
end;