The effect of cooling rate during punching process on the microstructure and mechanical property of the 22MnB steel was investigated by three different processing conditions i.e. the processes with and without argon protection as well as a simulated industrial process. The results show that the cooling rates of all the hot punched parts with the three different processing conditions are higher than the critical cooling rate of 22MnB5 steel, thus the hot punched steels with a microstructure of lath martensite exhibit tensile stresses higher than 1500 MPa. When the temperature of hot punch tools is higher, an oxide scale appeared on the punched workpiece surface, thereby, the cooling rate and the mechanical property of the steel become lower, and the martensitic plate becomes thicker. The hot punched part with tensile strength about 1600 MPa and strength multiplied ductility c.a. 20, 000 MPa% was available by heating with argon protection while reducing the initial temperature of punch tools to ambient temperature. This is because the cooling rate of the punched part was high and thereby the martensite plates of the steel became fine for the process with protective gas.