Whether the aircraft is in flight or on the ground,fire is very dangerous for civil aircraft. In order to ensure flight safety,the airworthiness provisions require that the fire zone and non-fire zone of the aircraft must be protected by firewalls for fire isolation,and at the same time put forward the verification requirements for firewalls. Civil aircraft pylon is connected to the power plant,and there is a designated fire zone for the power plant,so it is necessary to design a firewall at the interface between the pylon and power plant. Normally,there is a relative movement between power plant and pylon. In order to meet the fire protection design requirements,fire protection seal and related support structures are usually designed for fire protection sealing. This paper mainly conducts verification research on the fire seal at the interface between pylon and power plant based on the requirements of airworthiness clauses,relevant AC and international standards,proposes a complete analysis and test verification method,and verifies the pylon and sealing of a certain type of aircraft through fire tests. The power plant seal design meets the fire protection requirements and provides a reference for the fire protection compliance verification of the seal design of the pylon and power plant interface of civil aircraft.