To optimize steam distillation extraction process of volatile oil from Clematis Manshurica combined with anti-inflammatory index.Methods:With the volatile oil extraction rate,inhibition rate of NO and weighting score as indexes,effect of mesh number,liquid ratio and reflux time on steam distillation process of volatile oil from Clematis Manshurica were investigated by orthogonal test to optimize the best test scheme.Results:Effects of three factors on volatile oil extraction rate,inhibition rate of NO and weighteing score were in order of mesh number,liquid ratio,and reflux time; Optimal extraction technology was followed:mesh number was 3#,liquid ratio was 1:10,and reflux time was 12 h; volatile oil extraction rate was 0.072%,the inhibition rate of NO was 117.411%,weighting score was 97.979.Conclusion:The volatile oil extracted from steam distillation method has significant anti-inflammatory effect and the optimized process is stable and reliable.