The O-type ball valve serves as an important fluid control equipment in the coal chemical industry. However, during the operation process, cavitation phenomenon is very easy to occur inside the ball valve which will greatly affect production safety. The working medium of the ball valve is a fluid containing solid particles, and the volume fraction of particles will affect the cavitation, but the mechanism of how the fraction of particles affect cavitation is not clear. In order to solve this problem, numerical simulation is used to investigate the effect of solid phase volume fraction on cavitation in ball valve under different ball angles. The degree of cavitation in the ball valve can be illuminated by the pressure, cavitation number, and gas phase volume fraction on the valve ball outlet section. The results show that when the ball angle is 30° and 45°, there is no cavitation in the valve under any solid phase volume fraction. However, when the ball angle is 60°, different solid phase volume fractions have different effects on cavitation. When the solid phase volume fraction increases from 0% to 10%, the cavitation degree in the ball valve is gradually weakened. When the solid phase volume fraction increased from 10% to 20%, cavitation in the valve gradually increased. In addition, it is interesting that when the valve ball angle reaches 75°, cavitation in the ball valve will be promoted by any solid phase volume fraction. A lot of work has been done in this work to reveal the influence mechanism of solid phase volume fraction and ball valve angles on cavitation characteristics of O-type ball valves, and some useful results have been obtained, which has a certain guiding on controlling the working environment and multi-phase flow simulation of O-type ball valves.