Abstract: The bottom support layout of a large liquid hydrostatic turntable has a significant influence on flatness error for a hydrostatic guide. To study how to reduce the flatness error under the condition of turntable subjected to load, the reconstruction method of the bottom support layout on a turntable is proposed, after analyzing the influence of the parameters related to the bottom support layout on the flatness error. Initially, the parametric model of the bottom support layout is established, and then the flatness error under the condition of different bottom support layouts subjected to rated load is analyzed based on the finite element method(FEM). The flatness error value is obtained, and MATLAB curve fitting tool is used to study the influence of the turntable bottom support layout on the hydrostatic guide flatness error. On this basis, the bottom support layout of the turntable is reconstructed. The results show that the load capacity of the hydrostatic turntable improves with the reduction of the flatness error.