In this paper, hydraulic fracturing in fractured rock masses are studied using peridynamics, with a special attention to the interaction mechanisms between hydraulic fractures (HFs) and natural fractures (NFs).To achieve this objective, a two-dimensional numerical model is firstly analyzed to understand the effects of the in-situ stress, fracturing fluid viscosity, fracturing fluid injection rate, fracture friction coefficient and fracture approach angle on the interaction between HFs and NFs.The obtained results reveal that larger in-situ stress ratio, elevated friction coefficient, increased fluid viscosity, enhanced injection rate and wider approach angle create more favorable conditions for HF penetration into NF.After that, the fracture morphologies in fractured rock are analyzed under three-dimensional, successfully reproducing the 'diversion' interaction pattern between fractures, a phenomenon unattainable in 2D modeling.It was observed that there exists a mixed interaction mode between penetration and diversion, particularly when the length of NF is limited and the angle between NF and HF is less than 90°.Finally, the propagation of HFs within a 3D fractured rock mass featuring arbitrarily distributed joints (NFs) is simulated, providing new insights into complex real-world scenarios.