The use and maintenance stage accounts for the largest proportion of the product life cycle. Conducting research and application of digital technology for complex products in business scenarios of the use and maintenance stage is significant for accelerating the digital transformation of the complex product manufacturing industry and improving the service guarantee efficiency of complex products. This paper focused on the core business of the use and maintenance stage and deeply analyzed the requirements and complexity of digital features of complex products for use and maintenance, proposed description and integration methods of digital features of complex products, guiding the aggregation and encapsulation of technical information for use and maintenance. The feasibility, effectiveness, and practicality of the proposed methods are verified through case studies, laying the foundation for constructing digital twin equipment for complex products.