The invention discloses a high-voltage circuit breaker and a power measuring system including the high-voltage circuit breaker. The disclosed high-voltage circuit breaker comprises a single-pole double-throw type circuit breaker, wherein the single-pole double-throw type circuit breaker comprises a support part composed of a first single-pole part, a first fixing part, a second fixing part, a suspension part and a first single-pole part, wherein the fixing end of the first single-pole part is used for connecting to the high-voltage conductor; A movable end of the first single knife portion forhorizontally connecting to the first fixing portion or vertically connecting to the second fixing portion, the first fixing portion for connecting to the output end of the high-voltage power supply,the second fixing portion for connecting to the hanging portion, the first fixing portion being disposed at a position higher than the second fixing portion; The suspension part is connected to the second fixing part; The support portion of the first single-cutter portion is configured to provide support to the first single-cutter portion during the transition of the moving end of the first single-cutter portion from the connection with the first fixing portion to the connection with the second fixing portion by the action of gravity. The disclosed technical solution can accelerate the circuitbreaker speed.