Objective:To optimize extraction process of Rosmarinus officinalis L.oil by steam distillation.Methods:The proper extracting condition is optimized by orthogonal tests with the amount of the oil yield,extracted α-Pinene,and eucalyptol as index of evaluation.Results:Raw Rosmarinus officinalis extracted with 30 times of water for 2 hours is the optimum extraction process for the extraction of rosemary essential oil by steam distillation.Conclusions:The optimized extraction condition is stable and practicable ...