Abstract: The initial in-situ stress of rock mass is an important part of underground engineering research. Relying on the large-scale underground plant project, the three-dimensional hydraulic fracturing method and the conventional hydraulic fracturing method were used to measure the in-situ stress of hole ZK1 in the tunnel and surface hole ZK2 respectively to obtain the initial in-situ stress of rock mass. Based on the measured data, the three-dimensional numerical simulation method was used to calculate the in-situ stress field inversion, and obtained the distribution law of the in-situ stress field in the required engineering area. The results show that the initial in-situ stress can be effectively obtained by the hydraulic fracturing method, and the underground stress obtained by the three-dimensional hydraulic fracturing method is more accurate and can be confirmed by the vertical hole test data. The calculated value of in-situ stress obtained by numerical simulation is consistent with the measured value. The layout of plant tunnels is reasonable, and the probability of rock burst in the engineering area is low.The field in-situ test results and the regression in-situ stress field distribution rules can provide effective scientific support for engineering design.