A certain civilian helicopter is planned to be equipped with advanced avionics systems, and more functions will be implemented by software. The airworthiness certification of the helicopter will involve a large number of software reviews. It is necessary to clarify the review ideas and principles of software in the early stages of the project. On the basis of investigating the procedures and methods of foreign certification authorities for airworthiness review of airborne software, and based on domestic certification practices, and combined with the actual situation of the helicopter, the review ideas and principles of its onboard software were studied. Specifically, two principles of review were proposed. Firstly, a risk-based approach was proposed to determine the level of review intervention. Secondly, the principle of reusing tool identification data was proposed, as well as acceptable compliance methods for previously developed software. As a preliminary study on the airworthiness review of the airborne software of this type of helicopter,it can provide certain references for the development department and the airworthiness review teams of this aircraft.