The invention discloses a processing method for preparing refined rosemary extract, and belongs to the technical field of separation and purification of natural compounds. By the processing method, the refined rosemary extract with the total content of carnosic acid and carnosol reaching 50-70% is prepared by the following steps: with a commercial crude rosemary extract as a raw material, preparing a crude rosemary extract fine filtrate, preparing extractant liquid, preparing rosemary extract extraction liquid, preparing rosemary extract reextraction liquid, preparing the refined rosemary extract and preparing regenerated extractant liquid. Trialkyl phosphine oxide is used for extracting, so that the separation efficiency is high, the extraction rate of the carnosic acid and the carnosol in the rosemary extract can reach 99.8%, and the reextraction rate of the carnosic acid and the carnosol can reach 95.7%; an operation method is simple, the equipment investment and the operating costare low, and energy-saving and environment-friendly requirements are met; the used extractant liquid can be reused after being regenerated, an ethanol solution can be recycled for reuse, and no three-waste pollution is caused, so that the processing method is a typical environment-friendly processing method.