Hello! I have a student visa. In case it expires when am at my home country, what do I need to do?

If you hold student X1 type and residence permit, once your residence permit expires when you are in your home country, you need to start all over again to re-apply for a new X1 type and enter PRC to get a new residence permit.
Actually, it will be a little bit troublesome, so you are advised to renew your residence permit before you leave PRC. If so, you don’t need to worry anymore.