After booking a hotel on Ctrip. Com, should I remember the order number?

No, they will know when they get to the hotel and match their names, as long as they have contact information. The contact information is that they are afraid of not arriving at the hotel on time, so they call to postpone it, otherwise it will be cancelled automatically. After cancellation, you can stay even if you have a room, but you can't enjoy that price. I have encountered this problem and spent more money for nothing.