To ensure the stability and security of the communication network of the smart substation, the switch port access control strategy of the communication network in the smart substation is put forward. The smart substation communication mode and network structure are introduced, the potential safety hazard and the switch port access control requirements of smart substation are analyzed. The theory and technical characteristics of the port security based on static MAC address are explained, and the networking mode, theory, authentication process and technical characteristics of the port security based on IEEE802.1X protocol are elaborated. The application cases and implementation schemes of port security strategy during the present time in smart substation are concluded. In conclusion, to control the switch port security of the smart substation, the strategy combining with the static MAC address and IEEE802.1X protocol is valid, feasible and practical at present.