The burial depth, lithology, and geological structure affect the spatial distribution characteristics of geostress. Under complex geological conditions, in-situ stress does not always increase linearly with depth and is affected by changes in lithology and geological structure. Taking a tunnel with a maximum depth of 2 268 m in the Tianshan Mountains as an example, based on site surveys and measurement data, the finite difference software FLAC^3D was used for three-dimensional numerical simulation in an area of about 460 km². Results show a clear impact on abnormal varations of in-situ stress due to geological structures. There is a 5 ~ 10 MPa difference in the fluctuation of in-situ stress caused by sudden changes as folds on both sides of the fault, especially the local concentration of in-situ stress near the hanging wall of the fault. Such kind of concentration mostly contributes to the occurrence of rockburst once excavating at sections of hard rocks. Compared with the measured in-situ stress results at nearby locations, the numerical calculation results are 20 ~ 30 MPa larger, indicating a significant change in in-situ stress values due to the development of geological structures, which is also a location that the in-situ stress measurement points are trying to avoid in practice. The research results connecting simulation with measurement are expected to provide reference for similar projects in this area.