Using the mechanical effect of the ultrasonic wave, the ultrasonic welding promoting technique has been presented. The ultrasonic wave generating device generates a high frequency oscillation signal; a high frequency mechanical vibration,converted by the piezoelectric transducer, transmits to the medium; the ultrasonic wave radiates forward in the solder solution, resulting in a strong pressure and an instant oscillation in the solder solution, lowering the surface tension of the solder solution, ensuring the expansion, flow and infiltration of the solder solution on the welding surface, so as to improving the infiltration of the solder solution. Experimental results show that the ultrasonic welding promoting technique can enhance the infiltration of the solder solution on the wire and the welding quality has been significantly improved.