My mother loves to check my mobile phone since she was a child. I'm a college student now, and she's still looking into it. What's more, I get angry when I look at it in front of me. What should I do?

Setting a password is not appropriate, and it is not a fundamental solution. You should talk to her. You need privacy and your own space. It's disrespectful of you to rummage through my mobile phone like this every day. When I was a kid, you went through my cell phone. I can imagine that you are afraid that I will make bad friends. Now that I am in college, I have the ability to distinguish right from wrong. Will you do this again when I step into the society, get married and have children? I can't have no discrimination at all. Maybe she was not used to it at first. You can say you want to show it to me, and then you can tell her who the people are, regardless of gender, classmates and friends. You can tell her something interesting that happened between you and your classmates and friends before, and she will gradually understand it and won't turn it over. I don't think you should say anything to your mother. She's worried about you, too, and so are you.