The extendable trailer can be freely extended and retracted according to the length of the goods to meet the transportation needs of goods of different sizes. Through the advanced hydraulic telescopic system, the length adjustment operation of the vehicle is simple and fast, and the telescopic operation can be completed in a short time. The body adopts a modular design, and the components are tightly connected to ensure that the structural strength and stability of the vehicle are not affected during the telescopic process. The telescopic semi-trailer has a strong carrying capacity and can transport extra-long goods, such as building materials, bridge components, etc. In addition, the extendable lowboy trailer is equipped with advanced braking and suspension systems to ensure safety and stability during transportation, and plays an important role in large-scale engineering construction and transportation.