Abstract: In order to solve the problem of high time cost faced by the Buck/Boost bidirectional DC-DC converter in the optical storage system when using the Model Predictive Control with Finite Control Set（FCS-MPC）, this text discusses an Event-Triggered Finite Control Set Model Predictive Control（ET-FCS-MPC） way. Generally,the online optimization problem is cleared up in each control cycle,to achieve the control scheme of FCS-MPC.However, online optimization solution will increase a large amount of calculation time and switching losses. FCSMPC is activated by the system solely when the error norm surpasses a predefined threshold, utilizing eventtriggered control. This superfluous optimization operation can be reduced without sacrificing the performance of keeping the deviation between the target system’s state and its reference within a preset threshold. A simulation model was ideated in MATLAB/Simulink, which certificated that this method decreased a great deal of calculation and time cost while maintaining satisfactory adjustment performance.