Objective In this study, two-dimensional ultrasound was used to carry out in vitro and in vivo experiments. A new and more practical bladder volume measurement formula was calculated with a large number of data, and its accuracy was verified.. Methods Two-dimensional ultrasound was used to measure the maximum cross-section diameter, the maximum cross-section diameter and the maximum longitudinal section diameter. The accuracy of the new formula was compared with that of ellipsoid formula and Lambert empirical formula The error and accuracy of the three formulas are analyzed again.. Results The training set data obtained four new formula coefficients:k1=0.6244,k2 =0.6399, k3=0.6713, and the average coefficient k=0.6542.The analysis and validation set data obtained that the average coefficient k error of the new formula is the smallest, r2 was close to 1. The correlation between predicted data and real data was 0.998, and the intra-group correlation coefficient was 0.996,which was significant((P<0.05), the error of the new formula (V=0.6452lwh) is smaller than that of the ellipsoid formula and the Lambert empirical formula (r2 is close to 1) . Conclusions Different coefficients were more accurate in different volume intervals, and the error of k=0.6542 was smaller when the training set was not divided into different volume groups or clinical work. Keywords: bladder; volume; two-dimensional ultrasound; new formula