Abstract: For problem that it cannot real-timely judge running state of equipment in coal preparation plant by use of parameter threshold method, a comprehensive running state evaluation system for equipment in coal preparation plant was designed. The system selects evaluation indexes and describes state of the evaluation indexes, then establishes membership function and determines weight of each evaluation index, finally calculates running state value of equipment through fuzzy comprehensive evaluation, so as to predict development trend of running state of equipment according to the state value, and provide countermeasure support for maintenance work.