Abstract: As an important branch of the underwater robot industry, bionic robot fish plays an important role in exploring marine resources. This paper discusses the application of BeiDou Satellite Navigation System (BDS) in bionic robot fish and the basic positioning principle of bionic robot fish based on BDS. A multi-navigation combination technique is proposed. The modular design of bionic robotic fish mechanical structure based on BDS is used to explain the application of BDS in bionic machine fish posture calculation and path planning technology. The hardware system of the system's bionic robot fish is designed and based on BDS realized on the bionic robot fish designed by the laboratory.