A device for testing infiltration capacity of a frozen soil side slope during raining belongs to the field of civil engineering equipment, solves the problem that the traditional device for studying the rainfall infiltration capacity cannot be used for studying the infiltration capacity of frozen soil, and includes a refrigerator box, a soil sample box, a refrigerator box cover, a Markov bottle, a water temperature regulator, a raining device, sunshine simulation equipment, a slope surface water collecting tank, a box bottom water collector and a monitoring element, wherein a refrigerating fluid pipe is laid on the inner wall of the refrigerator box in a curved manner; an inlet and an outlet are arranged on the box wall of the refrigerator box and connected with a pipeline of a refrigerating machine outside the refrigerator box; the water temperature regulator is placed in the Markov bottle, and the water temperature of the Markov bottle is 5 DEG C to 30 DEG C; and the sunshine simulation equipment is installed above the soil sample box. The device is used for simulating the infiltration condition of the frozen soil side slope during raining, studying the influence degrees of all the influence factors on the rainfall infiltration capacity and providing the reference for the evaluation on the frozen soil slope stability, thereby being used for guiding the design and maintenanceof the side slope project for railways and highways in frozen soil areas.