Rare earth gypsum is an industrial by-product generated from the treatment of wastewater produced by the rare earth metallurgical process, and its recycling is a strategic measure for the current green metallurgy and cleaner production. In addition, the filler reinforcing agent for natural rubber in polymers is mainly carbon black or other materials such as calcium carbonate, which will cause a large amount of carbon emissions in the production process. Calcium sulfate whisker (CSW) is a new reinforcing agent in rubber composites, while its surface is hydrophilic and has poor compatibility with organic matrix. This work aims at the above problem by using inorganic trisodium phosphate-organic stearic acid composite modification, thus changing the surface polarity of CSW and improving the compatibility with organic matrix.