The invention discloses an electric power circuit breaker. The electric power circuit breaker comprises a base cylinder with an insulated surface. Two ends of the base cylinder are sealed. A rotation shaft with an insulated surface is arranged in the base cylinder. The rotation shaft is driven to rotate by a drive handle arranged out of the base cylinder. A static contact is arranged on the inner wall of the base cylinder. A movable contact is arranged on the rotation shaft. An axial magnetic field is formed between the base cylinder and the rotation shaft. A temperature compensation system is arranged in the base cylinder. The temperature compensation system comprises a temperature compensation chamber. Triggering holes are arranged at two sides of the temperature compensation chamber. System sensors are arranged in the triggering holes. A temperature compensation magnetic connection tube is arranged in the temperature compensation chamber. A temperature reducing medium is arranged in the temperature compensation magnetic connection tube. A drainage device is also arranged in the temperature compensation chamber. According to the electric power circuit breaker, sudden temperature reduction can be rapidly carried out in an area generating electric arc; moreover, a relatively strong arc extinguishing mode can be realized in a relatively small area by matching a magnetic blow arc extinguishing mode; the arc extinguishing performance is improved; the high security performance is realized; and the actual use demand is satisfied.