попробуйте этот код
QAxWidget *flash = new QAxWidget(0, 0);
flash->resize(500, 400);
HWND hWnd = (HWND)flash->winId();
LONG lStyle = ::GetWindowLong(hWnd, GWL_STYLE);
lStyle &= ~(WS_CAPTION | WS_THICKFRAME | WS_MINIMIZE | WS_MAXIMIZE | WS_SYSMENU);
::SetWindowLong(hWnd, GWL_STYLE, lStyle);
LONG lExStyle = ::GetWindowLong(hWnd, GWL_EXSTYLE);
::SetWindowLong(hWnd, GWL_EXSTYLE, lExStyle|WS_EX_LAYERED|WS_EX_TOPMOST|WS_EX_TRANSPARENT);
typedef int (WINAPI* LPFUNC)(HWND, COLORREF , BYTE, DWORD);
HINSTANCE hins = ::LoadLibraryW(L"User32.DLL");
if(!hins)
return ;
LPFUNC func2 = (LPFUNC)GetProcAddress(hins,"SetLayeredWindowAttributes");
if(!func2)
return ;
COLORREF clrMask = RGB(255,255,255);
func2(hWnd, clrMask, 0, LWA_COLORKEY);
FreeLibrary(hins);
flash->setControl(QString::fromUtf8("{d27cdb6e-ae6d-11cf-96b8-444553540000}"));
flash->dynamicCall("LoadMovie(long,string)", 0, "d:/9023.swf");
flash->dynamicCall("WMode", "transparent");
flash->show();
показать activex с прозрачным фоном.