Автор: http://www.swissdelphicenter.ch

uses
  ComObj;

function Xls_To_StringGrid(AGrid: TStringGrid; AXLSFile: string): Boolean;
const
  xlCellTypeLastCell = $0000000B;
var
  XLApp, Sheet: OLEVariant;
  RangeMatrix: Variant;
  x, y, k, r: Integer;
begin
  Result := False;
  // Create Excel-OLE Object
  XLApp := CreateOleObject('Excel.Application');
  try
    // Hide Excel
    XLApp.Visible := False;

    // Open the Workbook
    XLApp.Workbooks.Open(AXLSFile);

    // Sheet := XLApp.Workbooks[1].WorkSheets[1];
    Sheet := XLApp.Workbooks[ExtractFileName(AXLSFile)].WorkSheets[1];

    // In order to know the dimension of the WorkSheet, i.e the number of rows
    // and the number of columns, we activate the last non-empty cell of it

    Sheet.Cells.SpecialCells(xlCellTypeLastCell, EmptyParam).Activate;
    // Get the value of the last row
    x := XLApp.ActiveCell.Row;
    // Get the value of the last column
    y := XLApp.ActiveCell.Column;

    // Set Stringgrid's row &col dimensions.

    AGrid.RowCount := x;
    AGrid.ColCount := y;

    // Assign the Variant associated with the WorkSheet to the Delphi Variant

    RangeMatrix := XLApp.Range['A1', XLApp.Cells.Item[X, Y]].Value;
    //  Define the loop for filling in the TStringGrid
    k := 1;
    repeat
      for r := 1 to y do
        AGrid.Cells[(r - 1), (k - 1)] := RangeMatrix[K, R];
      Inc(k, 1);
      AGrid.RowCount := k + 1;
    until k > x;
    // Unassign the Delphi Variant Matrix
    RangeMatrix := Unassigned;

  finally
    // Quit Excel
    if not VarIsEmpty(XLApp) then
    begin
      // XLApp.DisplayAlerts := False;
      XLApp.Quit;
      XLAPP := Unassigned;
      Sheet := Unassigned;
      Result := True;
    end;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  if Xls_To_StringGrid(StringGrid1, 'C:\Table1.xls') then
    ShowMessage('Table has been exported!');
end;