Abstract: In order to conduct and accurate evaluation on the joint quality of spot welding by using ultrasonic echo transmitting signals,a software system of ultrasonic inspection and joint quality evaluation has been developed on the platform of VB6.0.The software system achieves the transmission and storage of the data of ultrasonic signals in the digitab oscilloscope by calling TekVISA ActiveX controllers supplied by Tektronix Inc..Based on the principle of ultrasonic inspection for joint quality of spot weld,a proper evaluation on the joint quality of spot weld can be carried out by selecting and calculating the main characteristic parameters. The software has a friendly interface and can be operated easily.It has been proved that the evaluation rule is correct,so the software can be applied to the ultrasonic inspection and evaluation for joint quality of spot weld.