Using the extraction yield of Fructus Schisandrae seed oil as an index, the ultrasonic extraction process of it was optimized by single factor and orthogonal design. HPLC was used to analyze the content of schizandrin A, B, and schisandrin in the seeds. The mice liver injuried model was established by administration with CCl₄ and the contents of GSH, MDA and SOD in mice liver tissue were determined. HE staining was used to observe the pathological changes of liver. The results showed that the optimum process was as follows: the extraction solvent was n-hexane with the ratio of solid to liquid was 115 (g/mL), treated by the ultrasonic power at 80 W for 2 h at 50 ℃. The extraction rate of Fructus Schisandrae Seed Oil was 29.94%. The content of different components was detected as 4.0% of schizandrin A, 1.95% of schisandrin B and 0.13% of schisandrin. The injury of the mice livers could be successfully induced by administration with 0.2% concentrations of CCl₄. The high, medium and low doses of Fructus Schisandrae Seed Oil could significantly reduce the MDA (P<0.05 or P<0.01) and increase the levels of SOD and GSH (P<0.05). The HE staining results showed that schisandra seed oil could significantly inhibit the edema and necrosis of the mice livers.