A new lateral shearing beam-splitter based on a new method to split light is proposed. The principle of its structure is elaborated and analyzed,and the results of its application in FTS have been discussed. When the structures of beam-splitters are in the same size,this structure can generate ten times of the spacing more than generated by others. When it is applied to FTS,the FTS can reach high resolving power without increasing the size of the structure and the weight of it. There is no light to return to the source when the beam-splitter splits the light,so the energy of light in this method would be almost twice of that of the Sagnac method. Furthermore,compared with the Mach-Zehnder method,the realization of this method is easier. Its structure is compact and stable,can be used in the domain such as aviation,astronautics remote and sensing,and also works well in the material ingredient analysis field.