The invention provides a control method of a controllable arrester. The controllable arrester is composed of a controllable part and a fixed part, wherein the controllable part and the fixed part areconnected in series. The controllable part is switched through a control switch connected with both ends thereof. When the control switch is closed, the controllable part drops out. When the control switch is opened, the controllable part is in. The control method comprises the steps that line electrification detection is carried out; the controllable part is controlled to be connected in parallelwith opening and closing of the control switch according to the detection result, so that in and out of the controllable part automatically cooperate with opening and closing of a line switch; at thesame time, the running state of the control switch connected in parallel with the controllable part is monitored in real time; and when the control switch is abnormal, the line switch is operated inlinkage. The invention further proposes a control system of the controllable arrester. According to the invention, the control system of the controllable part of the controllable arrester and the control system of the line switch can be decoupled; the logic reliability of the controllable part in closing of the lock line switch is improved; and the intervention of operating personnel is reduced.