Hebei went to school in Anyang because of the epidemic. Can the teacher isolate him for a week before going to school?

There is a high probability that it can't be.

It depends on the regulations of your own school, so you'd better ask the leaders of your school, because sometimes 7 days of isolation does not necessarily mean safety. General study will not let you go back to school, but may let you continue to be isolated or do nucleic acid testing.