Abstract: Digital image technigue is one of the newest development in the application of computer science.The paper has made some approaches to the new applications of digital image technique in welding field.Three different resolutional interfaces for inputting image(8 bit,4 bit,binary) are designed and built.And welding image processing,welding image pattern recognizing and feedback auto-controlling have been made by these interfaces.The paper introduces also some research works by this technique in brief,including the measuring of brazed area,the measuring of temperature distribution in welding process,the detection of welding defects on x-ray film,and the on-line detection of welding line.It has been shown that development of digital image technique would make possible its wide application in welding processes.