Abstract: For rock mass engineering in frozen areas,rocks are often subjected to coupling fatigue damage caused by freeze-thaw cycles and periodic load disturbances. To study the fatigue cracking propagation of freeze-thaw fractured granite and quantify the degree of damage and classification types of cracks,three periodic load tests under stress amplitude were conducted on double-fractured granite after 40 freeze-thaw cycles. Real-time acoustic emission and high-speed photographic monitoring technology were employed to reveal crack evolution,and different crack cracking types were further classified to aid in understanding dynamic fracturing laws. Additionally,the relationship between mesoscopic pore characteristics and macroscopic mechanical properties of fractured granite was analyzed through nuclear magnetic resonance testing. The results demonstrate that with the increase in amplitude-stress ratio of the periodic load,the double-fractured granite experiences a "silent period" during the periodic load. The proportion of shear cracks generated by double-fractured granite during periodic loading stages is greater than that during monotonic loading stages,and the rock is prone to forming shear failure cracks under high amplitudes. Furthermore,the maximum value of acoustic emission from double-fractured granite decreases,indicating a decrease in large-scale fractures. Additionally,the angle of the extended crack to the end face of the outer tip of the prefabricated fracture of the rock sample is larger under periodic load. The fatigue life of double-fractured granite decreases,the development of internal microfracture propagation slows down,and the H-containing fluid that can be stored is also reduced,ultimately manifested as a decrease in the area change rate of the nuclear magnetic resonance T₂ spectral area.