This paper introduces the method of using LabVIEW and Matlab mixed programming in order to solving the problems, such as complex inputting data, network communication, hardware control, interface development and poor in procedures control in using Matlab alone. Confirm the image read method, gather images form LabVIEW and setting them to Matlab for complex calculation, then send them to LabVIEW for image output and display. The result shows that the method can realize the flaw image processing of tunneling, and it can be used for other parts flaw detection.