The invention provides a sliding door design method and a sliding door sharing structure. The method that the sharing structure comprising multiple sharing parts is used for designing a sliding door suitable for different vehicle models is adopted, so that the technical problems that a sliding door in the prior art is unique in form and cannot meet different requirements, development cost is high,and a manufacturing period is long are solved, and the effects that completely different sliding door structures can be arranged on a side wall, brand-new vehicle models do not need to be developed for different sliding door structures, the development workload and development cost are greatly reduced, the different requirements of clients can be met, the sharing performance of the parts is quitehigh, and development cost is effectively saved are achieved.