This is the drug particles automatic packaging machine design. First reference to the similar packaging machine, explores many works and transmission, and pointed out the various works and the advantages and disadvantages of the transmission mechanism; and then focuses on the research and design of the transmission system, according to the packaging process route, finalized design of the program. According to the results of comparative analysis to determine the eccentric sprocket mechanism, feeding mechanism, longitudinal sealing mechanism, horizontal seal mechanism, cutting mechanism; in this design, my main task is to improve the eccentric sprocket mechanism makes packaging machines adapt the corresponding range of bag length, improve production efficiency.