The invention discloses an output chain wheel structure of a motorcycle engine. The structure comprises an output chain wheel body. The outer surface of the output chain wheel is coated with a vibration reducing layer, a splined hole is formed axially in the center of the output chain wheel body, annular bosses which extend backwards are separately arranged at two axial ends of the output chain wheel body, and the inner walls of the annular bosses are inclined surfaces. According to the structure disclosed by the invention, noise generated in the engaging process of a chain and the output chain wheel in the operating process of a motorcycle is effectively lowered, and the driving performance is enhanced.