The strapping machine adopts relay-contactor control system, has many disadvantages, and has single function. On the basis of the analysis and control requirements, the SIEMENS S7-200 programmable controller was adopted. The main circuit diagram of the strapping machine, the PLC input and output connection circuit diagram, the brake and the heating circuit were designed. The cycle flow chart and the ladder chart program of the strapping machine were completed. PLC control system for line connection and the electrical-mechanical alignment, the strapping machine can achieve manual, automatic and continuous 3 functions, to meet the control requirements.