Abstract: Petri net is a suitable tool for describing asynchronism and concurrency of events in computer system models. It can be effectively used to perform formalized verification and behaviors analysis for parallel and concurrent systems. In this paper, based on the basic definition of fuzzy Petri nets, the fuzzy production rule representation of weighted fuzzy knowledge is discussed. The mapping relations and the steps of transforming between weighted fuzzy production rule and fuzzy Petri nets are established. Several interrelated issues in knowledge representation based on Petri nets are solved on the basis of extensive fuzzy Petri nets. Finally, the calculation of uncertainty and imprecise reasoning procedure of fuzzy Petri nets are also provided.