The invention discloses an automatic feeding device for a centerless grinder and a using method thereof, comprising a body, a feeding platform is arranged on one side of the body, a feeding assembly is arranged on the feeding platform, and a feeding platform is arranged on the other side of the body , there are feeding components evenly distributed horizontally on the feeding platform, a first transfer component is provided on the side of the feeding platform close to the feeding platform, a second transferring component is provided on the side of the feeding platform close to the feeding platform, the first transferring component and the The second transfer assembly is matched, and the first transfer assembly and the second transfer assembly transfer the workpiece from the feeding assembly to the feeding assembly; its use method includes: a, preparation before use; b, discharging; c, feeding; d , the transfer of the workpiece; e, feeding. The invention avoids the phenomenon of the workpiece falling during the conveying process, prevents the workpiece from colliding in the process of being sent into the centerless grinder, greatly improves the processing efficiency, and reduces the processing loss rate.