exactly this one i needed ... thank you very much .....
QMenu* pushMenu = new QMenu(pushButton);
QCalendarWidget* pushCalendar = new QCalendarWidget(pushMenu);
QWidgetAction* pushAction = new QWidgetAction(pushMenu);
pushAction->setDefaultWidget(pushCalendar);
pushMenu->addAction(pushAction);
pushButton->setMenu(pushMenu);
in place of calender i have to use another widget ..... i get it ..