With the widespread application of integrated modular architectures in avionics system,partitioning should be taken into account in the design of Flight Management System (FMS).We made ananalysis to software hosted rules under integrated architecture,studied the partition requirement of ARINC702A,and proposed a partitioning design scheme for implementing flight management functions.Finally,the core functions of FMS were developed,and a testing method was given.Our research can provide a reference for the development of FMS for integrated modular avionics system.