The extraction of natural pigments from walnut green husks can not only develop its application value but also reduce the environmental pollution． The main component of walnut green husk pigment is tannins． The tannins in walnut green husk are extracted by microwave-assisted ethanol extraction． Firstly，this article studies the effects of solid-liquid ratio，ethanol volume fraction，extraction temperature，extraction time and microwave power on the extraction yield of tannins，and then optimizes the extraction process by response surface methodology ( ＲSM) ． The optimal conditions are: ethanol volume fraction of 45% ，solid-liquid ratio of 1∶ 20 ( g /mL) ，temperature of 61℃，microwave power of 612 W，and a time of 10 min． Under these conditions，the extraction yield of tannins in walnut green husk is 20. 36 mg /g． The results provides the basic data and theoretical guidance for the extraction of tannins from walnut green husk