The invention provides an ultrahigh voltage AC switching-type controllable arrester separate structure. An arrester body is arranged on an arrester support; a control unit is arranged on a control unit support; the arrester support and the control unit support are arranged parallelly; the arrester body comprises a fixing element and a controlled element, and the control unit and the controlled element are connected parallelly; according to the working condition of the circuit of the arrester body, the control unit controls connection or disconnection between the controlled unit and the circuitto limit operation overvoltage in the case of closing and re-closing of a circuit breaker in the circuit. The ultrahigh voltage AC switching-type controllable arrester separate structure and the aseismic checking method thereof have the beneficial effects that an operation overvoltage flexible limiting method based on adaptive operation condition changes is provided, the arrester separate structure is designed, and through arranging the controllable arrester at a substation line side and arranging a conventional arrester in the middle of the line, the operation overvoltage in the circuit canbe deeply reduced, and the closing resistance in the circuit breaker is thus cancelled.