The invention relates to the field of grouting equipment, and discloses a one-way ball valve for a piston type grouting pump. The one-way ball valve comprises a valve tube, a spring, a valve ball anda flow guide tube, a casing tube is arranged outside the flow guide tube, the flow guide tube carries out longitudinal moving in the casing tube, the top of the casing tube is fixedly connected with the top of an inner cavity of the valve tube, and an upper cavity is formed in the top of the flow guide tube. According to the one-way ball valve for the piston type grouting pump, through the designthat the flow guide tube can move relative to the casing tube and a magnetic ring plug, when the grouting pump above the valve tube carries out slurry suction, the valve ball moves upwards and makes contact with the flow guide tube, the flow guide tube is driven to move upwards, the pressure intensity, below the magnetic ring plug, of the upper cavity of the flow guide tube is increased, gas flowor slurry carries out impact on the contact portion of the valve ball and the flow guide tube, a sticky solid stuck on the contact portion of the valve ball and the flow guide tube is flushed away, itis ensured that the valve ball is tightly attached to the flow guide tube, seal is effectively achieved, it is ensured that when the grouting pump works, slurry cannot flow back, amount of each-timegrouting is not reduced, and the grouting efficiency is effectively ensured.