Abstract: A compressor suction valve plate fracture accident occurred. The fracture cause of the valve plate was analyzed using macroscopic observation, chemical composition analysis, metallographic examination, hardness testing, scanning electron microscopy and energy spectrum analysis. The results show that there were obvious corrosion points and sulfide inclusions distributed in intermittent strips inside the structure of the suction valve plate, which reduced the mechanical properties of the suction valve plate. The material itself had a high hardness, and stress concentration occurred at the waist of the valve plate. Microcracks were initiated at the inclusions, and under stress, the cracks continued to propagate,and ultimately led to early brittle fatigue fracture of the suction valve plate.