Abstract: The artificial neural network was introduced into welding expert system and a series of neural network models were set up by the authors for the design of welding parameters.These models were trained with actual welding procedure data. Testing results of these models show that they possess strong abilities in self-learning, self-adapting, error tolerating, coordinating and associating. The research of this paper has solved the most difficult problem of welding procedure design expert systems-the design of welding parameters. This opens up a new direction for the study of welding expert systems.