The telescopic cantilever rack is composed of columns, bases, telescopic arms, transverse tie rods, inclined tie rods, top beams, transmission boxes and other parts. The column is a thick-walled rectangular tube, the base is H-beam with a section size of 200×200, and the cantilever fixing and telescopic parts are also made of rectangular tubes. The base, the cantilever and the column are fixed by high-strength bolts. The telescopic arm can be shaken out through the corresponding joint on the transmission box, which is convenient for cargo storage and retrieval.