Abstract: This paper addresses the risk of sudden falling during the operation of double-layer simple cargo elevators used in polyester plants by designing and implementing a PLC-based anti-falling device. The study first outlines the purpose of developing this device, which is to prevent elevator falling incidents and ensure the safety of personnel and equipment. Methodologically, the project team utilized four magnet-equipped cylinders installed on both sides at the second floor to push cylindrical straight shafts against the elevator car when it is docked, thereby forming a mechanical lock; the shafts retract automatically when the elevator descends. The control system employs a PLC program, which was compiled and debugged to establish a closed-loop control system incorporating various protective actions such as automatic operation and disengagement, operation, and stopping. Address allocation and program compilation were carried out based on the existing equipment. The results demonstrate that the anti-falling device modification is low-cost, and the modified system performs safely, reliably, and is user-friendly, effectively preventing elevator falling risks and achieving the intended safety protection objectives.