Abstract: The development and use of high-strength and high-toughness automotive spring steel has become the main means to reduce the mass of heavy duty trucks, and it is important to adopt advance heat treatment process to improve the strength and toughness of spring steel. Taking a newly developed 1800 MPa class 52CrMn steel as the object, with the heating temperature, tempering temperature and tempering holding time as the design factors, the tensile strength and fracture elongation after heat treatment as the response index, several groups of heat treatment experiments of spring steel under different process parameters on the basis of the response surface method were designed. The optimum combination of quenching and tempering heat treatment of 52CrMn steel was obtained, and the law of the material properties variation with each process parameter was also explained by metallographic observation. The results show that the strength and toughness of 52CrMn steel under different heat treatment process parameters can be accurately predicted by the established response surface model. The optimal heat treatment process of the steel is the heating temperature of 880-900 ℃, the tempering temperature of 370-380 ℃, and the tempering holding time of 30-50 min. The tensile strength of the steel is higher than 1800 MPa and the fracture elongation is 8.61%, which can ensure that the spring steel owns high strength and sufficient toughness after heat treatment.