Abstract: In response to the real-world needs of marine development, underwater detection, and marine protection, a novel bionic flatworm robot is designed based on the principles of bionics and robotics. The robot uses a multi-group of symmetrically arranged and interconnected flapping fins to achieve sinusoidal flapping motion, which drives the robot's underwater bionic swimming. The kinematic model of the flapping fins is established, and the kinematic parameters of the bionic flatworm robot are analyzed and determined. The motion simulation results of the flapping fins verify that the robot can swim stably, the motion model is established correctly, and the correctness of the design scheme and theoretical analysis is proved, which provides a new solution for the design of underwater bionic robots.