Temperature is the main factor that affects the stability of magnolia rostrata extract. The thermal stability of magnolia rostrata extract is studied. The contents of honokiol and magnolol in the extract obtained by CO2-supercritical fluid extraction(SFE-CO2)were determined by HPLC during the drying process at different temperatures, and the degradation equations of these two ingredients were explored. The degradation reactions of magnolol and honokiol in the drying process were first-order, and the rate of degradation was faster at 100℃. Higher temperatures were selected to examine the accelerated degradation isothermally, and the shelf lives of honokiol and magnolol were found to be 1125.6 h and 975.7 h at 25℃. In order to guarantee the preparation quality lower temperature and shorter time during drying and storage for the SFE-CO2 extract of magnolia rostrata is preferable.