Objective To evaluate the accuracy of three-dimensional reconstruction of gallbladder volume based on CT images, and to study the biomechanical changes of gallbladder movement, to explore the relationship between gallbladder dynamics and gallstone formation. Methods A method of calculating gallbladder volume based on CT three-dimensional reconstruction of gallbladder model is proposed, and compared with ellipsoid method. Construct a finite element model of the gallbladder and perform fluid dynamics analysis to simulate the functional changes in gallbladder motility under different angles of convergence between the cystic duct and common bile duct, as well as in the presence of gallstones. Results The mean error of specific gallbladder model volume and ellipsoid volume of 50 patients was 7.26% and 25.35%. The maximum pressure, maximum deformation and maximum flow velocity of pear-shaped gallbladder during the refill period were significantly greater than those of gourd-shaped gallbladder. The angle between the gallbladder duct and the common bile duct had little effect on bile flow pattern, and the maximum bile flow rate was reached when the Angle was 120°. The bile flow velocity of gallbladder with calculus is smaller than that of gallbladder without calculus, and there is a vortex near the calculus. Conclusion The calculation of gallbladder volume based on CT 3D reconstruction is more accurate than ellipsoid method. Compared with pear-shaped gallbladder, gourd-shaped gallbladder has lower gallbladder wall contraction and bile flow rate, and poor motor function. The bile flow rate of the gallbladder is slow, which is more likely to lead to the enlargement of stones or the formation of new stones.