The invention relates to a method for decolorizing sugar juice by using a magnesium silicate membrane, which comprises the following steps: preparing magnesium silicate by using a sacrificial template-hydrothermal method, preparing the magnesium silicate into a membrane, and filtering and decolorizing the sugar juice by using the magnesium silicate membrane. The magnesium silicate has the structural advantages that the magnesium silicate is formed by stacking nanosheets, the overall structure is porous and spherical, the particle size distribution is uniform, the performance is stable, and themagnesium silicate can be repeatedly used. By optimizing the preparation process of the porous magnesium silicate and the application of the membrane of the porous magnesium silicate, the decolorization rate of the porous magnesium silicate to syrup reaches 80% in the sugar juice decolorization process, and another technical scheme is provided for the sugar juice decolorization process in the sugar industry. According to the method, green and easily available silicate is used as a decolorizing agent, the method belongs to a sulfur-free sugar making process, efficient clarification and decolorization of the sugar juice can be realized without using toxic sulfur dioxide gas, and the problems of environmental pollution, sulfite residue and the like are avoided.