Abstract: The novel polar marine steel was heat-treated by the normalizing (N) and quenching and tempering (QT) processes. The tribocorrosion coupling effect of the heat-treated steels under different applied potentials in simulated low temperature seawater was investigated on a UMT-3 multifunctional friction and wear testing equipment equipped with low temperature and electrochemical modules. The microstructures and worn surface morphologies of the steels after the tribocorrosion tests were characterized by scanning electron microscopy (SEM) and white light interferometry. The tribocorrosion mechanisms under different applied potentials were also explored. Results showed that, as the applied potential increased, the average friction coefficients of the heat-treated steels decreased, while the wear depths, wear weights, and corrosion currents increased. During the tribocorrosion tests, the open circuit potentials of the heat-treated steels shifted negatively and the corresponding corrosion densities increased obviously. Peeling pits could be mainly observed on the worn surface of the N steel, while small cracks and etch pits dominated on the worn surface of the QT steel. The volume losses caused by the wear and corrosion for the N steel accounted for 80.6% and 44.9%, respectively, which became 55.1% and 44.9% for the QT steel. The wear and corrosion processes of both the N and QT steels were mutual positively promoted, evidencing the presence of the synergistic tribocorrosion coupling effects.