The utility model discloses a tower body erecting and descending mechanism of a tower crane. The tower body erecting and descending mechanism is arranged on a tower body and a rotary table, the tower body comprises an upper tower body and a lower tower body which are hinged to each other, the upper tower body comprises an inner tower body and an outer tower body which are connected with each other in a sleeved mode, the tower body erecting and descending mechanism comprises connecting components, a tower pulling component, a jacking component and a locking component, and the tower pulling component, the jacking component and the locking component are respectively connected with the tower body through the connecting components. The upper tower body and the lower tower body are driven by the tower pulling component to rotate, therefore, the erection of the tower body is achieved, the inner tower body is jacked up through the jacking component, the inner tower body is made to be safely and reliably locked to a target position through the locking component, the tower erecting movement and the tower descending movement are made to be flexible and fast, the safety coefficient in the tower erecting and tower descending process of the tower body is greatly improved, and the tower body erecting and descending mechanism has the advantages of being simple in structure, easy and convenient to operate, wide in application range, safe, reliable and the like.