With the rapid development of aviation models, the degree of digitalization of avionics systems becomes higher and higher, and the proportion of the software in those systems becomes larger and larger. In this paper, software architecture and formal modeling of avionics systems are discussed. Further, a system level integrated testing method based on formalization for avionics system from static and dynamic aspects is proposed. At last, the effectiveness of the proposed approach is evaluated through an integrated testing system designed and implemented in this research.