Abstract: Based on the fault diagnosis of frequency convert system, flow and flow combination, on-site code is reduced, the difference of the same type of resource is eliminated by encapsulation technology and in-out data image, this paper realizes plug and play of part of the on-site resource.On-site resource and physics connection of computers are resolved by wireless communication technology, the average service time is reduced from 35.6 hours to 8.9 hours, and rate of fault recognition increase by 2 percentage points.