Effects of high pressure heat treatment on the microstructure refinement and corrosion resistance of brass were studied by means of metallographic observation, SEM/EDX, profilometer and CH1660A electrochemical instrument. Brass were heated from 23°C to 700°C and kept at 700°C for 10 minutes under high pressure of 1GPa, 3GPa, 4GPa and 6GPa, respectively. The results show that high pressure heat treatment has great influence not only on the microstructure refinement of the alloy but also on its corrosion resistance in HCl solution. Under 3GPa, the refined microstructure can be found and the corrosion resistance of the alloy changes into much worse. However, under a higher pressure of 6GPa, the corrosion resistance increases and the microstructure refining effect is not obvious. All the findings of this work were elucidated in terms of the change in the formation and growing of the crystal under a high pressure heat treatment condition.