Maxent model optimized by ENMeval is used to simulate the suitable areas of Miscanthus nepalensis in four periods, including the Last Glacial Maximum, mid-Holocene, present and the future(2061~2080), based on 60 occurrence localities and 9 bioclimatic variables. The importance of climatic variables is estimated by use of percent contribution, permutation importance and Jackknife test. The feature combination LQH and regularization multiplier 3 could generate optimal model; With the setting parament, area under receiver operating characteristic curve of test is (0.963±0.028) indicating highly accurate simulation accuracy. The main climatic factors affect the suitable areas of M. nepalensis are temperature seasonality (standard deviation), min temperature of coldest month, temperature annual range and annual precipitation. The highly and middle suitable areas of present distribution are mostly at eastern Xizang, southern Sichuan, western Guizhou and the great part of Yunnan. In the Last Glacial Maximum, it had the largest suitable areas, and coastal regions in the East China Sea and the South China Sea had suitable areas that were not found in other periods. In the mid-Holocene, the contour of suitable areas was similar to present suitable areas. In the future, the whole suitable areas would move northward. From the Last Glacial Maximum to the future, M. nepalensis may experience experiences three processes: inward contraction, basic stability, and overall northward migration.