Abstract: Aiming at the serious cavitation problem of mine water hydraulic support safety valve, a CFD multi-phase flow model of valve chamber was established. The pressure and gas phase distribution characteristics of valve chamber flow field were studied. The influence of valve core structure parameters (valve outlet row number, valve outlet number, hole spacing, hole diameter) on the cavitation characteristics of important valve orifice overflow section was analyzed, and the structure parameters of valve chamber were optimized. The results show that the maximum volume fraction of vapor phase decreases by 19.4% when the spool is two rows of orifices, the number of orifices is 16, the diameter of orifices is 1.4 mm and the spacing of orifices is 8 mm, which can inhibit the formation of cavitation erosion.