As the key equipment of flexible DC power grid,DC circuit breaker is used for fault fast isolation and recovery,which greatly improves the security and reliability of DC power grid. Based on the hybrid high voltage DC circuit breaker,the control,protection architecture and control protection strategy are studied in detail. First of all,the ‘redundancy dual’ control system architecture and the ‘two out of three’ protection system architecture are designed,which have the characteristics of clear architecture level and clear function allocation. Then,the opening and closing control strategies of the hybrid DC circuit breaker are given,and the overcurrent protection strategy,the main equipment protection strategy and the auxiliary equipment protection strategy are designed in detail. Finally,a set of control and protection system of 500 kV/25 kA hybrid high voltage DC circuit breaker is developed and simulated by real-time digital simulation system (RTDS). The results show that the control and protection system and its strategy are correct and effective.