Aimed at the problems of the task assignment and results fusion in fault diagnosis of the complex equipment, a certain type of ground-to-air missile fault diagnosis task model is described to make up for the weakness of CNP underutilization of empirical knowledge, and the case-based reasoning and CNP are combined. The traditional CNP task assignment method is improved, the detail description of algorithm is given, and the scope of the tender and the bid evaluation strategies are studied deeply.In order to solve the diagnosis results conflicts for the involvement of multiple diagnosis resource, the diagnosis fuzzy fusion algorithm is improved. The example of fusion results shows that the deviation of group decision can be corrected effectively.