With the dry rhizomes of Trillium kamtschaticum as materials, this experiment was to optimize the extraction process of diosgenin in Trillium kamtschaticum using UPLC method to determinate diosgenin. The influence of solid-liquid ratio, time and temperature on extraction contents of the diosgenin in dry rhizomes of Trillium kamtschaticum were discussed with orthogonal test method. Results showed that the impact sequence of the factors on theextraction contents of the diosgenin in dry rhizomes of Trillium kamtschaticum was as follows: extraction temperature＞solid-liquid ratio＞extraction time. The optimal extraction condition was solid-liquid ratio of 1∶8, extraction timeof 4 h, and extraction temperature of 80℃. In conclusion, extraction temperature is the main factor affecting the extracting contents of diosgenin. Under these optimal conditions, the extracting contents of diosgenin in dry rhizomes of Trillium kamtschaticum is 0.0791%.