During last ten years, change of consumption pattern, variety and modernity of consumers, variety of producers and competitors, changes and vacillation rates, cause developing and decreasing the amounts of produce expenses by using hardware and software progressing, which are so important. In this respect, one of the possible solutions to increase the quality and enjoy the use of software possibilities is to perform producing systems. The aim of this article is to choose, automatic process and welding technology by using WELD-EXP. software. In this software, experience and knowledge of skilled men and expert form the rules in the expert system and knowledge base. After interchange of information and receive the necessary data from user, this software by studying and analyzing necessary instances, choose and suggest the best welding process or processes. Finally, the users confirm and complete it and present the welding process specification (WPS). Therefore, this way is time-consuming and save the expense of making and producing of weldments.