Objective The motor function of gallbladder is very important for human health. Considering the characteristics of gallbladder under healthy and pathological conditions, this paper studies the biomechanics of gallbladder wall and the hydrodynamics of bile, as well as the correlation between the motor function of gallbladder and the genesis of gallstones. Methods The three-dimensional structure model of gallbladder was constructed by using CT image data. The finite element model was established to simulate the movement of gallbladder and the flow process of bile, which can analyze the movement mode of gallbladder and its influence on the formation of gallstones under different fluid solid coupling conditions. Results Under the same conditions, the flow velocity of calculous bile is lower than that of normal bile, and the flow pattern is more tortuous; The overall force, shape variables and the amount of contraction of gallbladder with weak motor function were smaller. Conclusion It is found that when the motor function of gallbladder is damaged and weakened, the contraction will be greatly reduced and gallstones are more likely to occur. The study of gallbladder motor function based on fluid-solid interaction can provide necessary theoretical basis and technical analysis means for the surgical treatment of gallstones.