Abstract: The effect of extraction of Michelia macclureiroot extracted by supercritical fluid on the seed germination of Pinusmas soniana was studied.The results show that the alleochemicals of Michelia macclurei root extracted by pure CO₂ have significantly inhibitory effects on the absolute germination rate，absolute germination power，plumular root length，plumular axis length，fresh weight and dry weight.On the contrary，the alleochemicals of Michelia macclurei root extracted by entrainer mixed with CO₂ have positive effects on the absolute germination rate，plumular axis length，fresh weight and dry weight，but have inhibitory effects on the absolute germination power and plumular root length.