According to the practical need for uncertain time modeling and analysis in WfMSs, based on possibility theory, the paper firstly introduces fuzzy time and puts forward the concept of Extended Fuzzy Timing Workflow Nets (EFTWFN). Then, we present the modeling method to construct the EFTWFN models of concurrent workflows with resource constraints. Subsequently, the simulation of fuzzy time and transition firing possibility of EFTWFN models are discussed, and the simulation method of EFTWFN models is proposed. In the end, our modeling and simulation methods are validated by explaining a real example of manufacturing enterprise with CPN Tools.