If we arrive by subway to the north entrance of summer palace and walk to east entrance how go back

If you just want to finish the sighseeing after you arrive in the east gate, just get out and take city bus back to the city center. It seems there is no vehicle inside the part from the east gate to the north. You can just walk. The park is closed at 18:00 and the combined ticket is 60RMB for the adult. Perhaps 50 percent off for the children.

Thank you for your answere Jerry