This brief focuses on the cooperative fault diagnosis of fuzzy time-delay fractional order multi-agent system (FOMAS) over directed networks, whose fractional order belongs to (0, 1). Due to the interconnections, for each agent’s estimator, when estimating the local state and error parameters, whose purpose is to further consider faulty effects on others. Firstly, by the interconnection relationships between each agent, a new formulation scheme is proposed so that the shared signals are achieved by correctly constructing auxiliary graphs of a directed network. Then, unlike the existed papers dealing with normal fuzzy multi-agent systems, new admissible criteria of fuzzy FOMASs are proposed with time-varying. Finally, to illustrate the method proposed above is available, a practical application example of unmanned aerial vehicles is given.