The invention belongs to the field of preparation of marine electrochemical sensors. A sensor for monitoring current of a sacrificial anode during cathode protection comprises a standard resistance, a current probe shell, a current sensor shell, epoxy resin, current probe covers, a current sensor cover, a leading-out wire used for testing data and a leading-out wire used for connecting an anode, wherein one end of the current sensor shell is in open type, the current probe shell is arranged in the current sensor shell, the standard resistance is arranged in the current probe shell, the current probe covers are arranged at the two ends of the current probe shell, the current sensor cover is arranged at the open end of the current sensor shell, one ends of the leading-out wire used for testing data and the leading-out wire used for connecting the anode are respectively connected with the standard resistance, the other ends of the leading-out wire used for testing data and the leading-out wire used for connecting the anode are led out from through holes in the two sides of the current probe shell, and epoxy resin is filled between the current probe shell and the current sensor shell for sealing. The sensor for monitoring the current of the sacrificial anode during cathode protection is applicable to determination of an anode output current in a cathode protection system with the sacrificial anode in a marine environment, a preparation technology is simple, operation is simple, and performance is reliable.