Abstract: According to the physical and mechanical significance of the representative element volume (REV) of jointed rock mass, based on the validation of rock failure process analysis (RFPA) software by simulating the strength and failure mode of the jointed rock mass synthesized in laboratory, a RFPA-based approach for determining the REV of the jointed rockmass is proposed. In this approach, a two-dimensional joint network is generated is represented based on the Monte-Carlo simulation of joint network. And then, the joint data are imported into the RFPA in order to study the size effect and anisotropy of the elastic moduli, the compressive strength and the tensile strength of the jointed rockmass, based on which the REV size is determined. At last, aiming at the jointed rock mass around a tunnel at a certain underground metal mine, the size effect and the anisotropy of the parameters of jointed rock mass are numerically examined. The REV size of the jointed rock mass is estimated to be 6 m×6 m after the comprehensive numerical analysis on the elastic moduli, compressive strength and tensile strength of the jointed rock at different spatial scales and orientations of joint, which may lay the basis for further geomechanical study analysis on jointed rock mass.