The invention discloses a task-oriented multi-state cascaded repairable equipment weak part identification method and is used for solving the technical problem that the conventional spare part demand prediction method is poor in practicality. The technical scheme comprises steps of firstly analyzing the composition of the multi-state cascaded repairable equipment parts, determining the various operation and failure states of the parts and the whole equipment, and establishing the MMDD model by the fault tree analysis method; using the Boolean variable product to represent all paths from the root node to the final node in the MMDD model; calculating the availability model generation matrix and the reliability model generation matrix of each part of the multi-state cascaded repairable equipment, the transfer probability matrix in the task period, the transfer probability matrix in the normal operation state and the transfer probability matrix in the failure state of each part according to the Markov process; and finally calculating the task success importance degree of each part, performing sequencing from small to large, further determining the part of the larger importance degree value as the weak part of the multi-state cascaded repairable equipment. The method is good in practicability.