The utility model discloses a potential detection sensor including a graphite electrode, a reference electrode, an electrode pedestal, an electrode pedestal casing, a probe rod, a socket, a graphite electrode lead, and a reference electrode lead, wherein the electrode pedestal casing is sleeved on the electrode pedestal, one end of the graphite electrode lead is connected with the graphite electrode, the other end of the graphite electrode lead is connected to the socket through the electrode pedestal casing and the cavity in the probe rod, one end of the reference electrode lead is connected with the reference electrode, the other end of the reference electrode lead is connected to the socket through the electrode pedestal casing and the cavity in the probe rod, and the graphite electrode and the reference electrode are embedded into the electrode pedestal and are sealed by sealant to measure the electrode potential of the anode electrolyte or cathode electrolyte of an all vanadium redox flow battery(VRB). The potential detection sensor used for detecting the charged state of the electrolyte of the VRB is reasonable in design, convenient in operation, low in cost. By means of such a potential detection sensor, the SOC detection error is small and the detection is accurate; moreover, the potential detection sensor provided plays a guiding role in the maintenance and management work of the long-running vanadium pile electrolyte, thereby guaranteeing the safe and stable running of the pile.