The invention belongs to the technical field of biological extraction, and discloses a process method for extracting tannin from dioscorea cirrhosa lour. The process method comprises: crushing dioscorea cirrhosa lour, adding acetone, heating, carrying out ultrasonic extracting, cooling, filtering to obtain a tannin extraction liquid, purifying, and separating to obtain tannin. According to the present invention, on the basis of the single factor experiment, the response surface method optimization design is performed to obtain the influence degree of various factors on the dioscorea cirrhosa lour tannin extraction rate, wherein the influence degree sequentially is the temperature, the acetone volume fraction and the time from high to low; in the extraction process, the temperature is preferentially determined; the optimal extraction process conditions comprise that the dioscorea cirrhosa lour particle size is 60 mesh, the ratio of the material to the liquid is 1:10, the acetone volume fraction is 74%, the ultrasonic power is 240 W, the extraction time is 31 min, and the extraction temperature is 54 DEG C, wherein the experiment results show that the tannin content determined under the conditions is 32.27%; with the method, the extraction time is shortened, the extraction rate is increased, and the development and the application of the dioscorea cirrhosa lour are easily achieved.