Abstract: Abstract:?The study of land use in ethnic mountainous regions is of great practical significance to optimization of the spatial pattern of land and alleviation of poverty in the regions in question. In this paper, with 80 administrative villages in Nanjian Yi autonomous county in Yunnan Province as the evaluation units, an evaluation index system based on the “production-living-ecological” functions theory was established; on top of that, the spatio-temporal diversity and influencing factors of the multifunctionality of land use in the area during the period from 2008 to 2017, as well as their dynamic change, were systematically analyzed using the measurement model of multi-functionality of land use, spatial autocorrelation, geo-detector and other tools. The results indicated that: 1）from 2008 to 2017, the multifunctionality of land use in Nanjian Yi autonomous county improved fast, the level of multifunctionality in 2017 being almost 50% higher than that of 2008, with 67 out of 80 administrative villages across the county at intermediate level or above. In the meantime, the development of various functional levels was uneven. The ecological function of land use was the highest, while the production function and living function grew faster. Among the secondary functions of land use, the ecological conservation function and ecological purification function were higher, followed by the agricultural production function and social security function, and the residential support function and economic development function were relatively lower, but the economic development function changed the most.2）from 2008 to 2017, the multifunctionality of land use in Nanjian Yi autonomous county was found with obvious diversity in spatial distribution, showing a “higher in the north and lower in the south” spatial pattern of “one center and two sub-centers”. The spatial distribution of production functions therein was in clusters, and was expanding with the county town and the flat basin area of Gonglang town as centers; living functions, on the other hand, gradually decreased inside out along the 135°central axis, being higher in the north and lower in the south; ecological functions showed a downward trend from the east to the west, with administrative villages at top and higher levels concentrated in areas around Ailao Mountain and Wuliang Mountain. 3) From 2008 to 2017, the influencing factors of the multifunctionality of land use in Nanjian Yi autonomous county experienced great changes. Regional policies and economic factors, such as government capital investment, labor skill training rate, policy loans, etc., have become the leading factors of multi-function space differentiation of land use. The change of leading factors which shifted from natural resources endowment to socio-economic and regional political factors was dominated by enhancement and stability, with 5 enhancement factors, 4 stable factors and 3 weakening factors. Finally, according to the characteristics and influencing factors of multifunctional land use and its dynamic changes from 2008 to 2017, and in combination with the economic development status and land use practice of Ethnic Mountainous Regions, some suggestions are put forward.