The invention discloses a square wave chamfering circuit and a drive method thereof and a display panel. The circuit comprises an input module, an output module , a chamfering control module, a chamfering module and a capacitor module, square wave signals input into the signal input end can form signals in chamfering wave shapes when output to the signal output end through the coordination of the five modules, thus the output signals are changed from rectangular sudden change to slope slow descent, accordingly the adverse influences brought by electrical level sudden change when the square wave signals are changed from a high electrical level to a low electrical level can be reduced, and in this way, when the square wave chamfering circuit is applied to the display panel, the quality of displayed pictures can be improved.