This paper proposes a new design and realization method for interlock logic of converter station circuit breaker in middle. By using the CT secondary current of circuit breaker in middle as the starting quantity and combining with the different operation of both side breakers, the interlock logic of converter station circuit breaker in middle is judged. Interlock trip logics of AC line string with converter transformer or super group AC filter under different fault operation conditions are considered, showing a self-adaptive capacity. Simulation analysis result indicates the method can adapt different operation conditions of high capacity HVDC/AC system, and will make a intelligence diagnosis for the operation condition of interlock logic trip of circuit breaker in middle, such as breaker’s single trip, non-fault trip and so on.