The invention relates to a telescopic hypochlorous-acid-resistant auxiliary anode device. The telescopic hypochlorous-acid-resistant auxiliary anode device is characterized by comprising an auxiliary anode bar bearing body, an auxiliary anode bar, a polytetrafluoroethylene casing pipe and a cable waterproof cable; a first auxiliary anode bar bearing sub-body and a second auxiliary anode bar bearing sub-body are buckled and fixed to form the auxiliary anode bar bearing body, the upper portion and the lower portion of the second auxiliary anode bar bearing sub-body stretch outwards to form a first seal shell and a second seal shell, the first seal shell is provided with a through hole for paste fixing of the polytetrafluoroethylene casing pipe in a penetrating manner, and the cable waterproof joint is fixedly arranged in the second seal shell; and the auxiliary anode bar comprises a first auxiliary anode bar body and a second auxiliary anode bar body, the first auxiliary anode bar body is in threaded connection with the second auxiliary anode bar body, the first auxiliary anode bar body is inserted into the polytetrafluoroethylene casing pipe, and an outgoing wire at the bottom of the second auxiliary anode bar body is connected with an outgoing wire of a cable through the cable waterproof joint. The telescopic hypochlorous-acid-resistant auxiliary anode device can be used for the technical field of corrosion prevention of an ocean platform.