The weight of longan seed is seventy percent weight of fresh longan, and it is a kinds of biology resource available. The methods and conditions of absorption and desorption of longan seed flavonoids by macro-porous resin were studied. The facts of pH, temperature, concentration of longan seed flavonoids leaching solution which affect adsorption performances were researched, and the effects of kinds of elution agent and its dosage on ratio of extract were discussed. The results showed that macro-porous resin had remarkable ability in absorbing longan seed flavonoids. In optimum conditions, the kinds of flavonoids of elution solution with 50％ ethanol was determined by colour reaction, and the results were that the kinds of flavonoids of Longan seed including flavonones and flavonol.