This chapter introduces the structure and components of waste semi-trailers, along with their working principles, performance parameters, and overall design. Firstly, it discusses the functions, features, and structural principles of the waste semi-trailer. Secondly, the working principle is explained in detail, including the docking process with a waste compactor, separation from the compactor, and the procedure for unloading waste. Thirdly, the key performance parameters of the waste semi-trailer are presented. Finally, the chapter covers the overall design, focusing on the structural design, control system design, and hydraulic system design of the waste semi-trailer.