Abstract The S-type speed control is applied to the motion control of the stacker, and the S-type speed curve control is simulated by MATLAB to verify the feasibility of the optimal design. In practice, Siemens S7-300 is used for PLC programming to realize S-type speed curve control technology of stacker. The high efficiency, real-time and accuracy of the design realized the effective optimization of the speed of the stacker in the automatic stereoscopic warehouse.