The work aims to design the control system of pecan shell cracking and packaging automatic production line based on S7-200 PLC and frequency converter control, so as to adapt to the large-scale processing and production of pecans. By means of PLC and frequency converter control, PLC program was designed to enable the system to work according to the established process. Combined with Siemens SMART700IE LCD touch screen, the man-machine interaction was realized. After the implementation of the control system, the maximum pecan shell cracking rate reached 95.9%, the packaging quality was maximized, the kernel damage rate was as low as 11.06%, and the shell cracking quality was effectively verified. The real-time display, monitoring and control of the pecan shell cracking and packaging automatic production system are achieved.