The invention discloses a device and method for preparing a two-dimensional nanosheet material through cooperation of ball milling and cavitation. An output shaft of a motor is coaxially and fixedly connected with the center of a rotating disc, a spiral container is arranged on the front face of the rotating disc, the upper end of the spiral container is connected with an upper feeding and discharging head, and the lower end of the spiral container is connected with a lower feeding and discharging head; an upper magnetic force generator is arranged at the upper end of the upper feeding and discharging head, a lower magnetic force generator is arranged at the lower end of the lower feeding and discharging head, and the upper magnetic force generator and the lower magnetic force generator are the same in structure and each composed of a first connecting plate, a connecting rod, a second connecting plate, electromagnets, bridge type switches and a power source, wherein the multiple electromagnets are fixedly embedded inside the lower end of the second connecting plate, each electromagnet is wound with a coil, and all the coils are connected with the power supply through the bridge switches; a small-diameter section is arranged in the middle of the front surface of each coil of solenoid of the spiral container, and grinding balls can just pass through the small-diameter sections; and the two-dimensional nanosheet material is prepared by spontaneously generating cavitation through common ball milling, so that the efficiency and the preparation precision are effectively improved.