In order to solve the shortcomings of traditional soft set method, such as large subjective factors and small difference in results, a contribution rate analysis method of equipment system of systems based on improved soft set is proposed. The method is improved and perfected from the perspective of capability difference, capability support degree and capability value, and the equipment-capability matrix is supplemented through the index parameters of equipment, and an example of a team equipment system is analyzed, which is compared with the traditional soft set method. The results show that the improved soft set method is better than traditional soft set method.