谢谢各位 我有更好的方法了 : {*****子窗体建立监视函数,只需建立一次,否则直接显示*****} procedure OpenChildForm(FormClass: TFormClass; var Fm; AOwner:TComponent); var i: integer; Child:TForm; begin for i := 0 to Screen.FormCount -1 do if Screen.Forms[i].ClassType=FormClass then begin Child:=Screen.Forms[i]; if Child.WindowState=wsMinimized then ShowWindow(Child.handle,SW_SHOWNORMAL) else ShowWindow(Child.handle,SW_SHOWNA); if (not Child.Visible) then Child.Visible:=True; Child.BringToFront; Child.Setfocus; TForm(Fm):=Child; exit; end; Child:=TForm(FormClass.NewInstance); TForm(fm):=Child; Child.Create(AOwner); child.Update; end; 调用 OpenChildForm(Tpdm,pdm, Self);