Abstract: A method for verifying the diagnosability of distributed discrete event systems based on state estimation for distributed discrete event systems is proposed. Firstly, the diagnosability of discrete event systems is formalized. Then a diagnostic verification algorithm for distributed discrete event systems based on state estimation is proposed, and then the necessary and sufficient conditions for the diagnosis of distributed discrete event systems are deduced. Finally, The feasibility of the algorithm is verified by the actual example. Compared with the existing algorithms, the proposed algorithm does not require real-time synchronization of each station. It only requires communication between sites within a limited time delay. When the system scale is large, the time complexity of the algorithm is also significantly reduced.