I find that there are more than 50 views in one day. It is ridiculous. How can I find out who have view my profile
You can't. Besides, your profile is meant for viewing. Usually a surge in views means that you participated or were mentioned (directly or indirectly) in a popular thread. You could check and see if something you did seems somewhat popular.
Besides, there is a rumor that when you hit 1,000,000 profile views you get a free unicorn. So more views are great!