With the widespread use of embedded software in safety critical system, software safety assurance becomes one of research hotspots of software engineering. In this paper, a survey is presented on Software safety standards, methods and tools in aircraft systems. First of all, airborne software safety definitions and standards are introduced, and the safety analysis framework is also presented. Secondly, airborne software safety analysis methods are classified into three types, namely, software requirement elicitation and specification, safety standard oriented software development, and software safety property verification. Existing research and application of software safety analysis methods are reviewed according to these three types. After that, existing researches on safety evidence collection during airborne software safety assurance process according to airworthiness certification are summarized. Finally, potential research directions of airborne software safety assurance are discussed.