An access control device and an authentication control method, where the method includes detecting whether a packet that arrives at an access control device is an authentication start packet, where the authentication start packet is used to start an authentication process of a terminal that sends the authentication start packet, and restricting a rate at which the access control device receives an authentication start packet. It is detected whether the packet that arrives at the access control device is an authentication start packet, and the rate at which the access control device receives the authentication start packet is restricted. The rate at which the authentication start packet is received is restricted to control a quantity of terminals that enter subsequent authentication, which avoids an avalanche effect of wireless authentication caused when an excessively large quantity of terminals enter subsequent authentication simultaneously.