This article mainly introduced the design of the plastic rivets automatic assembly machine. Nylon rivets, also known as plastic rivets, plastic rivets are used to better flexibility performance nylon, hence the name. Like the name implies, the nylon rivet is a branch of the rivet. Its role is to play a riveting cooperation with two separate objects. Roughly principal is similar with metal rivets. At present, the plastic rivets are mostly manual assembly, the design of automatic assembly machine design for this assembly the way labor intensity, high efficiency, quality is not stable assembly defect. This paper focuses on the design of automatic assembly machines for plastic rivets in ratchet drive mechanism and the frame structure. Which describe the details of the ratchet drive mechanism in the rack gear of the pendulum, the ratchet pendulum gear design. And then set the relevant parameters of the relevant parts and draw three-dimensional model with Solidworks. Finally assemble the whole automatic assembly machine for plastic rivets. Machinery automation work by adjusting the software to adapt to the needs of good flexibility and is particularly suitable for multi-variety, small batch production, is to shorten product development cycles and accelerate the replacement of important ways.