In order to solve the complexity, randomness and fuzziness of equipment support effectiveness evaluation, an equipment support capability evaluation model based on group decision-making and cloud theory was established. First, the evaluation index system of equipment support capability was established according to the task demand. Second, the order relation and group decision method were used to calculate index weights, the calculation process was simple and fast, and could reflect group decision-making. Third, the cloud theory was used to the reasonable conversion between qualitative concepts and quantitative representations in which the hierarchical index polymerization process could be cleanly and accurately expressed. Examples show that the method is simple, the logical relationship is clear, and the calculation results are consistent with reality. It can provide a scientific and objective method for equipment support effectiveness assessment, and provide scientific basis for ensuring resource allocation.