Abstract: The effect of steam explosion on Ganoderma Lucidum extractive was evaluated by comparing the difference of functional components from treated and untreated Ganoderma Lucidum and the toxicity of extractive from Ganoderma Lucidum pretreatmented by steam explosion was evaluated. The evaluation indicators include extraction rates of Ganoderma Lucidum polysaccharide and Ganoderma Lucidum triterpene.The toxicity of Ganoderma Lucidum extract treated by steam explosion was evaluated by tests of acute toxicity and 30 days feeding test. The steam explosion for 150s at a steam pressure of 1.5MPa was effective pretreatment for the extraction of Ganoderma Lucidum polysaccharide and the polysaccharide extraction rate of treated sample was 10 times compared with the untreated sample (3h) . The steam explosion for 210s at a steam pressure of 2.1MPa was effective pretreatment for the extraction of Ganoderma Lucidum triterpene and the triterpene extraction rate of treated sample was 1.95 times compared with the untreated sample. The in vivo mouse toxicity test showed that there is no obvious toxicity of extractive from Ganoderma Lucidum pretreatmented by steam explosion.