This paper investigates the kinematic optimization of fish-like swimming.First,an experiment was performed to detect the motion of the fish tail foil of a fish robot.Next,the kinematic swimming model was verified experimentally using an image processing method.The model includes two rotational motions:caudal foil motion and foil-pitching motion.The kinematic model allows us to evaluate the influence of motion trajectory in the optimization process.To optimize the propulsive efficiency and thrust,a multi-objective genetic algorithm was employed to handle with kinematic,hydrodynamic,and propulsion models.The results show that the caudal length has a significant effect on the performance of the flapping foil in fish-like swimming,and its influence on the motion trajectory may increase the propulsive efficiency to as high as 98％ in ideal conditions.The maximum thrust coefficient can also reach approximately 3 in ideal conditions.