Ram air turbine(RAT)system is a kind of aircraft emergency energy, which provides emergency hydraulic source and / or emergency power supply for key systems of aircraft in case of loss of main and auxiliary power, so as to maintain the maneuverability of aircraft, which is significant for aircraft to deal with emergency. Referring to AP-21-AA-2011-03-R4 about aircraft life cycle certification process division and certification activities, combined with the development process of a certain type of civil aircraft RAT system, this paper determines the workflow and method of civil aircraft RAT system airworthiness engineering technology. Starting from identifying the certification basis, transform the clauses into requirements, which are implemented into product design; the compliance methods and verification ideas of clauses are clarified, and finally the airworthiness compliance matrix is formed. The workflow has been preliminarily verified by the development of a certain type of civil aircraft RAT system, which provides a reference for the development and certification process of domestic civil aircraft airborne system.