During the automatic flight of civil aircraft, the transition of automatic flight system modes is an important factor affecting safety. With the rapid growth of functions and complexity of modern civil aircraft airborne systems, the safety analysis and verification of automatic flight system mode transition in the requirement phase has become an important challenge. The complexity of flight mode transition is not only reflected in the interaction among multiple flight modes necessary during the automatic flight but also in the complex data and control cross-linking relationships between the mode transition process and the external environment. Additionally, these cross-linking relationships imply the safety properties of the flight mode transition process, which increases the application difficulty of formal methods. This study proposes a domain specific modeling and verification framework. First, a modeling language MTRDL for transition requirements of automatic flight system modes and a modeling method based on extended SysML language are put forward. Secondly, the safety property-assisted protocol method based on safety requirement templates is proposed. Finally, the effectiveness of the method in the requirement verification of automatic flight system mode transition is proven by a case study of a certain aircraft’s itemized requirements.