The section of the tower structure is divided into three types: circular section, triangular section and square section. Circular cross-sections and triangular cross-sections are basically not used now. The tower cranes produced at home and abroad all adopt square profile structure. Therefore, this design is also a square section structure. According to the different materials of the main chord, this square section tower can be divided into: the tower body angle steel welded grid truss structure, the main chord is a rectangular section grid truss structure with angle steel and stiffeners; the tower body is made of angle steel welded square steel pipes Grid structure and seamless steel pipe welded grid structure. The space truss welded by section steel or steel pipe has low cost and can meet the needs of work. Therefore, the main chord adopts a square tube welded with equal angle steel. This style has the advantages of convenient and flexible material selection.