Recently planning and functioning of a Chemical Process Systems (CPS) has become more essential and many sophisticated tools were used. In this article, the application of fuzzy logic and neural network based expert systems in CPS was discussed. A brief discussion on fuzzy set theory and its characteristics were presented. Also, the importance of knowledge based expert system on CPS to attain extreme production and high safety was sketched. It was observed that there are several expert systems biased only on fuzzy logic and neural networks; hence it is recommended that the fuzzy logic and neural networks based expert systems in chemical process systems will be an efficient one. The detailed components and its interactions of the classical expert systems were discussed.