The invention discloses a tensioning mechanism of a tying belt and a using method thereof. The tensioning mechanism comprises a locking spring, teeth, a cutter shell, a stopping sheet, a rolling shaft, a first connection sheet, a shell, a sliding groove, a first sliding block, a second connection sheet, a third connection sheet, a long spring, a hand shank, a second sliding block, a sliding rod, aconnection rod and a fourth connection sheet. The tensioning mechanism adopts a connection rod mechanism, the first connection sheet is driven to move towards the rear of the shell by triggering thehand shank, meanwhile, the first sliding block moves towards the rear of the sliding groove, at the moment, the teeth are engaged with the tying belt to drive the sliding rod and the second sliding block to move towards the rear of the shell together, in this way, switching of various kinds of motion modes is achieved through the structure, meanwhile, action is applied on the hand shank through the second connection sheet and the third connection sheet, and the hand shank bounces out and restores to the original position. The tensioning mechanism of the tying belt is easy to manufacture, highprecision can be easily obtained, wear is controlled to be small, operation is smooth, and the working efficiency is high.