In this paper, we deal with the synthesis about nonblocking check in fuzzy discrete event systems (FDESs) by using abstraction and observation equivalence of fuzzy finite automaton (FFA). In FDESs, such a check imposes a great computational challenge because of the complexity incurred by the composition of plants and the supervisors. With respect to ideas in modeling control system, we present procedure based on FFA abstractions, which removes internal transitions of irrelevant transitions, allowing the nonblocking check to be performed on relatively small automata.