Abstract: In the process of transforming the resource model of a uranium mine into the mining block model, the mixing of waste rock mixing at ore-rock junction has an important influence on the grade of mining block model. With the deepening of understanding, it is found that the grade of waste and the width of rock mixed zone are important factors affecting the grade of mining block model. This paper analyzes the principle of waste rock mixing, calculates different waste grades and rock mixing thicknesses, and fits the ore dilution law during mining operations. After multi scheme calculation, under the condition of determined mining block model size, it seeks a reasonable waste mixing model and calculates the grade after dilution. After comparison with actual production data, it achieves a good fitting effect.