Abstract: Objective To optimize the ultrasonic extraction of magnolol from Cortex Magnoliae officinalis.Methods Effects of experiment conditions,different solvents,the time of extraction,ultrasonic power and solvent to material ratio in the extraction of magnolol from Cortex Magnoliae officinalis by ultrasonic were studied based on single factor and orthogonal experiments.Results Ethyl acetate was the best extracting solvent determined by single factor experiments.The optimum extraction time,ultrasonic power and material to solvent ratio ranged from 60-80 min,150-200W and 1:15-1:25,respectively.In descending order of the impact on extraction rate based on the orthogonal experiment,the factors were material to solvent ratio,ultrasonic power and extraction time.The optimum extraction conditions found by single factor and orthogonal experiments were solvent of acetic ether,the extraction time of 70 min,and ultrasonic powe of 175W with the solvent to material ratio of 1:25.The extraction yield of magnolol from Cortex Magnoliae Offieinalis was 88.13%.Conclusion The ultrasonic extraction method is easy to handle with low cost,short extraction time and high extraction rate.