The invention discloses an ultrasonic-assisted punching process. The ultrasonic-assisted punching process comprises the following steps that a, a stainless steel sheet is placed on the upper surface of a lower punching die of a punching machine; b, a driving air cylinder is started, a piston rod of the driving air cylinder drives an ultrasonic amplitude transformer, an ultrasonic transducer and a punching tool head to move downwards through a movable mounting frame, and the punching tool head presses the stainless steel sheet tightly, wherein the pressure value of the driving air cylinder ranges from 0.13 MPa to 0.15 MPa; c, after the pressure of the driving air cylinder is maintained for 4.5-5.5 seconds, an ultrasonic generator is started, wherein the power value of the ultrasonic generator is 4200 W, and the vibration frequency of the ultrasonic amplitude transformer is 2000 Hz; d, after the ultrasonic generator is started continuously for 1.5 seconds and then is shut down, the driving air cylinder continues to maintain pressure; e, after pressure maintenance is completed, the driving air cylinder is reset; f, the stainless steel sheet is taken down from the lower punching die. Through the design of the process steps, the ultrasonic-assisted punching process can effectively improve the punching bent-forming accuracy, the punching load is small, and the energy consumption is low.