The Counter Propagation network is excellent in solving the sorted problems. It can sort effectively, and its algorithm is concise. This paper describes in detail the algorithm of CPnetwork and its improvement the addition of error processing and network testing functions. The authors developed its simulated software by using the Visual Basic 6.0 and utilized it to identify the oil water layers. Practice shows that the training period of the improved CPnetwork was short and its identification ratio was very high. It can realize the quick identification of oil-water layers and will hence have a very wide application prospect.