Abstract: Artificial neural networks model is a kind of network structure consisting of a large number of simple interconnected units which are also called nodes or nuerons.It has the capacity to simulate human brains.In the area of intelligent monitoring,artificial neural networks has been manifested greater potentiality due to its excellent abilities of parallel distributed processing,self-learning,self-organization and associative memory.In this paper, knowledge representation,associative memory are studied,BP nueral network algorithm and the problem which should be considered in intelligent monitoring were discussed. The Chip forms in turning process are also analyzed and diagnosed,which turns out to be satisfied.