The work aims to improve the stacking efficiency of packaging assembly lines. A double-stack high-speed stacking system for packaging lines was designed, which included shaping cache area, stacking execution area and lifting and wrapping area. With PLC as the control core, the system realized human-computer interaction through SMART 700 IE V3 touch screen, and control equipment such as stacking robots and automatic wrapping machines to complete the stacking and wrapping of cardboard boxes through synchronous command control. The effectiveness and stability of the system were verified by the actual experimental platform, and the system could carry out double-stack stacking and wrapping at the same time, which greatly improved the operation efficiency of the stacking line. The system studied in this paper improves the stacking efficiency of cartons and can promote the intelligent level of automated packaging lines.