AIM To elucidate the factors that affect the stability of magnolol and honokiol in CortexMagnolia officinalis (Houpo) in the process of extraction. METHODS The contents of magnolol and honokiol in Houpo SFE-CO_2 extract, treated on different conditions, were determined by HPLC. The shelf lives of magnolol and honokiol were also estimated. RESULTS The shelf lives of magnolol and honokiol were found to be 387 days and 476 days respectively at 25℃. CONCLUSION Temperature is the main factor that affects the stability of magnolol and honokiol. The degradation is in accord with the first order rate of reaction. High temperature should be avoided during the extraction, figuration and storage of the products.