The invention provides an automatic dust removing device, an operation method of the automatic dust removing device and a solar device. The dust removing device comprises a first frame, a driving device and a cleaning device. The driving device is mounted on a first frame, wherein the driving device comprises an air cylinder, an air pipe, a storage pipe, a bearing seat, a gear and a rack; the gear is supported on the bearing seat; the air cylinder is connected with the rack; the air cylinder is connected with the storage pipe through the air pipe; a coolant medium is stored in the storage pipe; the cleaning device comprises two guide rails, a sliding block, a sliding rod, a cleaning brush and a connecting rod; the sliding block is mounted on the guide rail; the sliding rod is arranged between two sliding rails and connected with the gear through the connecting rod; and the cleaning brush is mounted on the sliding rod. The solar device comprises a second frame, a solar panel and the automatic dust removing device. The solar device provided by the invention uses gas-liquid phase change for generating driving force, can be automatically cleaned twice every day, electric energy and water sources are not needed, and thus the cost is low.