Abstract: The high-voltage DC circuit breaker can quickly cut off the fault current and stop the fault part to avoid the impact on the AC system connected to it due to the shutdown of multi terminal flexible DC system. The system equipped with DC circuit breaker highly depends on communication data to judge the line fault, and quickly remove and isolate the fault through it. In order to improve the security, stability and power supply reliability of power system operation, taking ±160 kV high voltage circuit breaker control system and DC line protection strategy as an example, this paper studies its transmission channel mode, reliability and time delay, compares it with conventional protection, and summarizes the key technologies for communication transmission requirements based on high voltage DC circuit breaker protection strategy.