The invention relates to a circuit breaker and a realization method thereof, and particularly relates to a high-voltage DC circuit breaker and a realization method thereof. The DC circuit breaker, based on a secondary current transferring principle, comprises a main branch, a current transferring branch and an energy absorption branch in parallel connection. The DC circuit breaker is serially connected in a DC system. The main branch comprises at least one high-speed mechanical switch K and at least one current transferring module comprising a fully-controlled device in serial connection. The current transferring branch is a bridge circuit formed by thyristor valves, inductors and capacitors. The energy absorption branch is formed by a non-linear resistor. The invention also provides a high-voltage DC circuit breaker realization method. The circuit breaker provided by the invention has a simple topological structure, the control is simple and convenient, used power electronic devices are mainly half-controlled thyristors, the technology is mature, realization is easy, the current breaking ability is large, a voltage-withstanding grade is high, the extension ability is strong, and the cost is greatly reduced.