Abstract: This paper investigates the micro-mechanical response of supported joint under direct shear loading with the particle flow code. It builts the supported joint and unsupported joint numerical model successfully. It investigates the mechanical properties and failure mode of supported joint under direct shear tests and under different normal stresses. At the same time, based on the shear-displacement curve and peak shear strength of the numerical model, it investigates the macro-mechanical properties. Moreover, the failure characteristics of the bolted joint are also analyzed via the micro-cracks distribution. Detailed results are given as follows:(1)Compared to the unsupported joint, the shear stress curve of the supported joint shows obvious increasing trend at the post-peak phase. There is obvious difference between the shear stresses for unsupported and supported joints. (2)Due to the different inclination angles, the supported joint exhibits different failure modes. When the inclination angle equals to 90°, the failure of the joint concentrates at the contact point of the joint and bolt. While, with increases of the inclination angle, the failure of the joint gradually turns to tensile failure along the bolt and the tensile crack propagation in the rock. (3)With different joint roughness value, the influence of bolt angel on the shear strength is different. When JRC value is small, the bolt shown a great influence on the peak shear stress, but when the JRC is larger, the influence is weaken.