The utility model provides a SF6 supplement device of a high-voltage breaker. The SF6 supplement device comprises a SF6 pressure storage tank filled with high-pressure SF6 gas, a solenoid valve disposed on a connection pipeline, a detector, and a first controller. The SF6 pressure storage tank is connected with a SF6 supplement port of the high-voltage breaker through the connection pipeline. The detector detects pressure values of SF6 in the high-voltage breaker, and sends pressure signals. The first controller receives the pressure signals, and when the SF6 pressure value is lower than a preset low pressure value, the controller controls the solenoid valve to start, and when the SF6 pressure value is higher than the preset low pressure value, the controller controls the solenoid valve to close, and the first controller is connected with the solenoid valve. The SF6 supplement device enables to automatically supplement gas into the high-voltage breaker when the SF6 pressure in the high-voltage breaker reduces, and non-scheduled outage of the high-voltage breaker caused by reduction of the SF6 pressure is reduced, and operation reliability of the breaker is improved. The utility model also provides the high-voltage breaker with the SF6 supplement device.