Abstract: The imbalance thrust force method (ITFM) is widely applied in the field of slope analysis and design because of its simple model, explicit calculation process and ability to calculate the overall landslide thrust. Because the mechanical model of the slice method is a statically indeterminate model, the existing slice methods are derived from various simplifications, including ITFM. As a statically indeterminate model, the slice method theoretically has innumerable solutions satisfying the equilibrium conditions. Among these innumerable solutions, there are reasonable and more representative solutions, such as the solution with smaller safety factor. According to the idea of ITFM and following the principle of the limit state method for design and calculation, this study tries to find the maximum force between slices for ITFM solution, that is, the maximum thrust force. Under the premise of taking the overall safety factor of slope, the solution of this study ensures that the shear force between the slices does not exceed the shear strength between the slices, so that the maximum inter slice force can be transferred between the slices. The theoretical analysis and example calculation show that compared with the traditional ITFM, the improved method can obtain a larger landslide thrust of the corresponding sliding surface of the slope under the premise of meeting the limit equilibrium condition, and obtain a smaller safety factor than the traditional ITFM. This study is an significant and useful improvement on the traditional ITFM.