Inertial navigation system has the advantages of good autonomy, good concealment and strong anti-jamming ability. It is widely used in the fields of aviation, aerospace and weapon systems. Strapdown inertial navigation system (SINS) is a digital inertial navigation system which is fixedly connected with carrier. Digital signal transmission and communication are the premise and foundation of navigation. Based on the hardware architecture of DSP 28335, this paper designs the serial communication module of SINS, which can realize the high-speed serial communication between SINS and DSP. The validity and reliability of data communication are verified by experiments