In this paper, the diagnosability of patterns failures of fuzzy discrete-event systems(FDES) is investigated, where patterns failures may be triggered by sequences of events during system operations, and a verifier-based pattern diagnosis approach is proposed. Firstly, the notions of S-type pattern failure and T-type pattern failure are introduced in fuzzy systems. Then the diagnosability of S-type pattern failures and the T-types pattern failures of the FEDS are formalized. In order to verify the diagnosability of pattern failures of the FDES, a verifier automaton is constructed, and a sufficient and necessary condition for the diagnosability of pattern failures is presented.