Abstarct: As an efficient and useful technique, hydraulic fracturing has been used for recovery of hydrocarbon from unconventional reservoirs for decades. However, these reservoirs are mostly heterogeneous and they include variety of discontinuities which significantly affect the propagation of hydraulic fractures. Therefore, in designing phase of hydraulic fracturing, it is vital to know how hydraulically induced and natural fractures interact. In spite of massive attempts in this field, researches are on the way to better understanding of how a hydraulic fracture propagates in a naturally fractured reservoir. Response of a hydraulic fracture to reaching natural fractures is investigated in this study using hydro-mechanical coupling in Bonded Particle Model (BPM) and Smooth-Joint Method. Sensitivity analysis of approaching angle of natural fractures, shear strength of natural fractures and ratio of in-situ stresses showed that how these parameters influence the propagation of a hydraulic fracture in a reservoir with two parallel natural fractures. Simulation results show that although the shape of borehole pressure history curves for different approaching angles are almost the same, but fracture patterns and pore pressure distributions are different. So that the more angle between natural fracture and direction of hydraulic fracture, the more chance for crossing hydraulic fracture the natural fracture. Existence of a natural fracture with friction coefficient and cohesion of zero, causes the arresting of hydraulic fracture and dilation of natural fracture. By increasing the shear strength of natural fracture, the chance for crossing increases and dilation of natural fractures decreases. Minimum principal stress greatly affects the time of initiation and break-down pressure of hydraulic fracturing. Different ratios of in-situ stresses force the hydraulic fractures to change their behaviors after reaching the natural fractures. Results of this study are in a good agreement with classic analytical equations of hydraulic fracturing.