create variant array where we'll copy our data}
arrData := VarArrayCreate([1, StringGrid2.RowCount, 1, StringGrid2.ColCount], varVariant);

{fill array}
for i := 1 to StringGrid2.RowCount do
　for j := 1 to StringGrid2.ColCount do
　 arrData[i, j] := StringGrid2.Cells[j-1, i-1];

{initialize an instance of Excel}
xls := CreateOLEObject('Excel.Application');

{create workbook}
wb := xls.Workbooks.Add;

{retrieve a range where data must be placed}
Range := wb.WorkSheets[1].Range[wb.WorkSheets[1].Cells[1, 1],
　　　　　　　　　　　　　　　wb.WorkSheets[1].Cells[StringGrid2.RowCount, StringGrid2.ColCount]];

{copy data from allocated variant array}
Range.Value := arrData;

{show Excel with our data}