The invention provides a method for rapidly removing caffeine from tea crude extract, comprising four operational links: preparation of a water-based adsorption separation agent, dynamic adsorption, magnetic adsorption separation, and dynamic desorption. Through the water-based adsorption separation agent for preferential adsorption and magnetic separation of caffeine, the separation operation issimplified, no tedious pretreatment is required, no toxic or harmful chemical reagent is used, and the operation can be completed at room temperature. Meanwhile, the whole separation process is rapidand efficient and is a complete separation process. That is to say, high-purity extraction of caffeine and preparation of tea liquor rich in tea polyphenol and without caffeine are simultaneously realized.