Abstract: DH36 ship plate steel with different Ce contents was smelted using ZG-01 vacuum induction furnace, and the microstructure and mechanical properties of the test steels were analyzed. The results show that when the Ce content is 0.0092%, the test steel has good mechanical properties. Compared with those of the test steel without Ce, the tensile strength, yield strength, elongation, impact energy and hardness of the test steel with 0.0092%Ce all increase. With the addition of rare earth Ce, the grain size of pearlite and ferrite decreases, and the pearlite becomes more dispersive. The MnS, Al₂O₃ and MnS+Al₂O₃ composite inclusions in the test steel are modified to Ce-Al-O-Mn system composite inclusions, Ce-Al-O-Mn-S system composite inclusions and CeO₂ inclusions. The size of Al₂O₃ and other related inclusions in the steel is significantly reduced.