An access control method includes: receiving, by a network device, an access request message from user equipment (UE); determining, by the network device based on the access request message, a network slice that the UE requests to access; and when the network device determines to reject an access request of the UE for accessing the network slice, returning, by the network device, a rejection response message to the UE, where the rejection response message includes back-off condition information, and the back-off condition information indicates a condition under which the UE requests again to access the network slice.