The invention relates to a rolling brush device and a using method thereof. The rolling brush device comprises a supporting frame, an eccentric roller, a shell body, a piston structure and a brushingstructure, wherein the supporting frame comprises a pair of supporting rods which are arranged oppositely and connected with each other; the eccentric roller is rotatably arranged between the pair ofsupporting rods, and a liquid inlet flow channel used for delivering a rolling brush liquid is formed in the interior of the eccentric roller; the shell body is fixedly arranged on the eccentric roller in a sleeving mode, and a piston cavity which communicates with the liquid inlet flow channel and is formed in the radial direction of the eccentric roller is formed in the shell body; the end partof the piston structure is embedded in the eccentric roller, and the piston structure is movably arranged in the piston cavity; and the brushing structure is fixedly arranged at the outer circumference of the shell body in an inserting mode and communicates with the piston cavity. The eccentric roller is driven to rotate eccentrically when the shell body rolls, and then the piston structure is driven to reciprocate in the piston cavity, so that the rolling brush liquid in the liquid inlet flow channel is absorbed into the piston cavity, and the uniformity of painting can be effectively ensured.