yuan.Clear ;
yuan.Free;
为什么要Clear, 去掉!
而且,showmodal时候,yuan一定要是之窗体
procedure Tmanage.yuanClick(Sender: TObject);
begin
yuan:=Tyuancailiaochurukujilu.create(application);
try
yuan.FormStyle := fsMDIChild;
yuan.showModal;
finally
FreeAndNil(yuan);
end;
end;