Abstract: Hydraulic fracturing is a key technology for the exploitation of hot dry rock geothermal resources, and clarifying its fracture propagation mechanism is of significant theoretical importance for optimizing reservoir fracturing design. In this study, true triaxial hydraulic fracturing tests were conducted on granite to systematically investigate the control of in-situ stress on hydraulic fracture propagation behavior. A three-dimensional laser scanner was employed to accurately capture fracture surface morphology and analyze the response of fracture orientation (dip direction and dip angle) to in-situ stress. Concurrently, acoustic emission monitoring was used to reveal the rock damage evolution characteristics throughout the fracturing process. The results indicate that the in-situ stress state plays a decisive role in fracture initiation, propagation, and final geometry. Under high vertical stress differences, through-going fractures with high dip angles can be formed. Furthermore, the fracture strike exhibits a systematic deflection with an increasing horizontal stress difference. Notably, a significant acoustic emission hysteresis phenomenon was observed during granite fracturing, where AE activity persisted for a considerable duration after the occurrence of the main fracture and the subsequent drop in pump pressure. This suggests that subcritical crack growth and frictional sliding continue post-fracture. This study elucidates the fracture evolution and acoustic emission response during the fracturing of hot dry rock reservoirs, providing an experimental basis for the interpretation of microseismic monitoring and the assessment of long-term reservoir stability in fracturing operations.