A novel three-phase extraction and purification procedure was developed to prepare high-quality flavonoids from surplus tea leaves. Flavonoids were selectively extracted in ethyl acetate (EtOAc) by the EtOAc-water-leaf three-phase extraction, with 91.2% extraction efficiency, more than 50% higher than the traditional water extraction. The EtOAc extracts were purified by the EtOAc-water- montmorillonite/charcoal three-phase adsorptive purification at 98% recovery. Highly purified flavonoids were obtained with less than 1.0% caffeine. The overall flavonoid recovery reached 90.3%, more than 40% higher than traditional methods. This procedure highly simplified the processes and significantly increased the recovery of flavonoid production from tea leaves.