The current code simplifies the internal force calculation of caisson members，ignoring the constraints of the superstructure on the members.We carry out the comparative analysis of transverse mid-span bending moment and support bending moment results by considering the effective constraints of the superstructure on the members with results of code calculation pattern，and compare the internal forces within 1.5l at the top of the member and 1.5l at the bottom of the member under different calculation patterns.The results show that when the upper structure of the caisson imposes effective constraints on the members，the transverse mid-span bending moment of the upper part of the caisson member can be reduced by about 36%，and the support bending moment can be reduced by about 14%，which can significantly optimize the structural design.At the same time，it is necessary to calculate the vertical strength of the members.Although the structural constraint conditions are similar to those at the bottom，due to the different load distribution，the top of the member is not suitable for calculating the internal force by using the three-side consolidation and one-side simply supported model.The internal force distribution of caisson members is uneven.The internal force of the edge compartment is much larger than that of the middle compartment，and the bending moment increases by more than 30%.It is particularly noteworthy for the design of small caissons with less than or equal to 2 compartments.In this condition，it is recommended to establish an overall model for calculation.