In order to find out problems of the equipment maintenance support system, the cloud theory is introduced into the equipment maintenance support system assessment. On the basis of systematic analysis of the components of the equipment maintenance support system, the paper establishes the equipment maintenance support system assessment index system, designs the system assessment process based on cloud model, uses the standard cloud calculation model, the index weight calculation model, builds the cloud calculation model and the cloud similarity calculation model, and verifies the feasibility combination example of the assessment method. The application shows that the method can objectively describe the current situation of equipment maintenance support system construction, and provides reference for the next decision of equipment maintenance support system construction.