Objective To study the effects of the oil temperature on cathodic protection devices of submarine oil pipeline. Methods Referring to the testing standard GB/ T 17848—1999, the changing rules of corrosion potential and coupled current of the iron electrode, aluminum electrode and coupling electrode at different oil temperatures were analyzed through simulated seawater experiment. The working potentials of sacrificial anode at 25 ℃ and 75 ℃ were tested, and the current efficiency of anode was calculated. The corrosion morphology of anode was observed. Results In the range of 25 ℃ to 75 ℃, the corrosion potential of aluminum electrode increased, the corrosion potential of iron electrode decreased, the coupled potential shifted to positive value and the coupled current significantly increased with increasing temperature. Conclusion The protection potential and protection current efficiency of sacrificial anode decreased in 75 ℃ seawater when compared to those at 25 ℃.