The multi-hole drainage of the filling pipe can eliminate the self-flow slope angle of the paste, improve the effect of roof jointing in the quarry, and avoid the problem of roof sinking. In order to study the influence of the number of relief holes, hole spacing and hole diameter on the rule of multi-hole equivalent relief, firstly, the diameter of relief holes is initially determined through theoretical analysis, then the homemade multi-hole equivalent relief test device is used to carry out the multi-hole equivalent relief test, and finally the change rule of the pressure and flow rate of the relief pipeline is analysed by numerical simulation method. The results show that compared with single-hole drainage, multi-hole drainage can eliminate the self-flow slope angle and improve the roof catch rate of the quarry. The spacing of holes has the most significant effect on the uniformity of flow relief in the relief holes, followed by the number of holes. When the paste flows in the horizontal pipe section, the static pressure of the pipe tends to decrease along the flow direction, and negative pressure appears at the mouth of the relief hole. After the paste reaches a stable state, the flow rate of each relief hole is basically the same, and the uniformity coefficient reaches 98.8%, which can achieve the equal flow rate of multiple holes.