Wireless power transfer (WPT) technology has been paid more attention due to its safety and convenience. The control strategy is one of the core concerns for power electronics. This paper proposed a secondary periodic energy control (SPEC) method, which can be used for WPT systems and other topologies in power electronics. The energy flowing into the load in each switching period is regulated by controlling a DC/DC converter before the load. The SPEC inherits the advantages of primary periodic energy control in response speed, overshoot suppression, and mutual inductance variation. Moreover, it has higher accuracy and simpler circuits for implementation. Based on the WPT system with LCC-S compensated network cascaded with a buck converter. SPEC is verified both in simulations and experiments.