Abstract: The CO₂ supercritical extraction process of puerarin from Radix puerariae residue was optimized using orthogonal experiment.Based on single factor experiments, sample amount,extraction temperature,extraction pressure and time were selected for L₉(3⁴) orthogonal tests using the extraction yield of puerarin as index.The results indicated that the optimal extraction conditions were sample amount of 50 g,extraction temperature of 55 ^oC,extraction pressure of 16 MPa and extraction time of 90 min.Under the optimized conditions,the extraction yield of puerarin was up to 82.5%.

Key words: Radix puerariae residue, puerarin, supereritical, orthogonal test