In view of the complex procedures and low efficiency of the airworthiness verification for civil aircraft modifications, a structured CSTI model was proposed. The model was designed to standardize the airworthiness verification process by hierarchically analyzing modification requirements, matching airworthiness clauses, generating verification tasks, and determining verification indicators. The model was integrated with a digital airworthiness verification system and a database to enable the automated generation of verification tasks, the comparison of verification indicators, and the management of verification data. Taking the aircraft oxygen system modification as an example, the verification process and indicators were systematically analyzed, the verification tasks were guided, and the verification indicators were evaluated. The results indicate the feasibility of the airworthiness verification system and the applicability of the model. The potential for combining the model and system with emerging technology is discussed and relevant proposals are provided. The research outcomes provide an efficient and extensible solution for digital airworthiness verification of aircraft modifications and serve as a theoretical reference for the intelligent development of future airworthiness verification systems.