Technically, yes, you can cancel your hotel booking after your China visa is approved. However, doing so carries a non-zero risk that can create serious problems upon arrival. The flight and hotel bookings you submit are considered part of your declared travel plan. While many travelers cancel their initial “visa bookings” without issue, immigration officers in China reserve the right to verify your itinerary. If they find you have no confirmed accommodation, they can question your intentions, deny you entry, and even mark your record, making future visa applications more difficult.
