Abstract: A continuous annealing simulator was used to simulate different annealing processes for 1500 MPa grade hot forming steel 22MnB5. The mechanical properties were tested by tensile testing machine and a microstructure after annealing was observed by metallographic microscope. The effect of different annealing processes on the properties of 22MnB5 was studied and the metallographic microstructure of spcimen corresponding to the optimal properties was analyzed. The results show that, under the conditions of 100 m/min band velocity, heating temperature of 780 ℃, slow cooling temperature of 610℃, fast cooling temperature of 460 ℃ and aging temperature 430 ℃, the optimum performance is obtained, the yield strength is 486 MPa, the tensile strength is 623 MPa. The metallographic microstructure corresponding to the optimal performance is pearlite and ferrite, and the pearlite ratio is 40%-50%. The plate is used to simulate hot stamping parameters by flat plate quenching. After quenching, the properties meet the requirements of 1500 MPa grade hot forming steel, and the microstructure is all martensite without decarbonization layer.