AbstractKnowledge of the uniaxial compressive responses of rock mass is crucial for evaluating the stability of rock pillar in underground engineering. The inherent spatial variabilities of rock mass properties are generally ignored in the traditional stability evaluation of rock pillars. In this study, probabilistic analysis of rock pillar was carried out to investigate the compressive responses of spatially variable rock pillars with three-dimensional (3D) random fields. Three-dimensional random fields of rock mass properties were generated using the Cholesky decomposition method, which was implemented into the FLAC3D using the Fish code. The failure mechanism of spatially variable rock pillar and influence of spatial variability of rock mass properties on uniaxial compressive strength and Young’s modulus were investigated on the basis of the Hoek–Brown criterion with Latin hypercube sampling (LHS). Results indicated that the spatial variability of rock mass properties significantly influences the uniaxial compressive strength and Young’s modulus of rock pillar. The expansion of the plastic region has obvious directivity, which is closely related to the direction of the random field. The vertical scale of fluctuation has a greater effect on the mean value of the uniaxial compressive strength and Young’s modulus of rock pillar than the horizontal scale of fluctuation.