Abstract:Ultrasonic assisted method was used to investigate the exetraction of chlorogenic acid from Eucommia ulmoides leaves.On the basis of the single factor experiment，the box-benhnken center combination was used to carry out the three-factor and three-level experimental design，and the relationship between the process parameters and the response values was analyzed by regression，and the optimal process conditions were predicted.The chlorogenic acid content was determined by high performance liquid chromatography.The results showed that the optimal extraction conditions of chlorogenic acid from Eucommia ulmoides Oliver were as follows extraction time 75 min，methanol volume fraction 70%，ultrasonic power 270 W，extraction temperature 45 ℃ ，and the predicted yield of chlorogenic acid was 2.532 %.Under the experimental conditions，the extraction yield of chlorogenic acid was 2.529%.