Abstract: OBJECTIVE To study the optimum technique for extraction of volatile oil from herb of Chuanzhi Gao. METHODS To compare three extraction effects among steam distillation, immersion and ultrasound. An orthogonal design was adopted in the study. The contents of extraction ratio, Paeonol were used as indices of appraisal. RESULTS Ultrasound was the best extraction technology. The optimized extraction technology of Chuanzhi Gao was shown to be: six fold volume of Petroleum ether should be added to 1 volume of Chuanzhi Gao for 2 successive extractions with 20 minutes of each. The power of ultrasound was 250 W. CONCLUSIONS Comparing with steam distillation and immersion, ultrasound spends less time, has higher efficiency and less harm to the materiel after extracting. This extraction method is suitable for industrialized production.