Because there is not enough space,it is necessary to set the supporting structure to reduce excavation.At present,there is little study about complex lock chamber structure with supporting at home and abroad.Based on the practical engineering,this paper uses the elastic foundation beam method and the finite element method to analyze two kinds of chamber structures,and studies the influence on the internal force of the chamber floor caused by the support.The result shows that the maximum positive moment of the bottom plate of the lock chamber occurs at the high water level period and the maximum negative moment occurs at the overhaul period.The support can reduce the internal forces of the docking chamber structure floor and improve the safety of the structure to simplify the construction of the bottom plate.The effects of different materials on the internal force of the chamber bottom floor are different.The effect of the jointed wall support on the internal force of the floor is higher than that of the steel sheet pile.