function DesktopColor(const X, Y: Integer): TColor;
 var
  c: TCanvas;
 begin
  c := TCanvas.Create;
  try
  c.Handle := GetWindowDC(GetDesktopWindow);
  Result := GetPixel(c.Handle, X, Y);
  finally
  c.Free;
  end;
 end;
 procedure TForm1.Timer1Timer(Sender: TObject);
 var
  Pos: TPoint;
 begin
  GetCursorPos(Pos);
  Panel1.Color := DesktopColor(Pos.X, Pos.Y);
 end;