Abstract: The spatial characteristics of mountain ecosystems are affected by terrain factors. Clarifying the spatial differentiation characteristics of mountain ecosystem 
services is the basis of regional land use and ecosystem management. This study took the Upper Reaches of the Minjiang River (URMR) as study areas. The terrain gradient  characteristics of ecosystem service value under landuse change were identified using terrain index, relative rate of change and sensitivity coefficient based on landuse data and DEM data. The results showed that: (1) The landuse types in the URMR were dominated by woodland and grassland, which accounted for 60% and 30% of the total area,  respectively. During 2000 to 2010, the change of terrain index was obvious in 1- 4 terrain areas. (2) The total value of ecosystem services and the value of individual ecosystem  services in the URMR showed an inverted Vshape change with the increase of topographic area. During 2000 to 2010, the ecosystem service value (ESV) increased in 1-12 terrain areas and reduced in 13-20. (3) During 2000 to 2010, the trend of ESV in each terrain was consistent with that of the study area. In 1 terrain area, the change of ESV in the  topographic level was slightly higher than that of the study area. In 2-20 terrain areas, the change was nearly consistent with the study area. (4) The sensitivity coefficient  of the ESV in per unit area of landuse types in the study area was less than 1 and the change of the ESV in per unit area was lack of flexibility. It showed that the results  were credible. During 2000 to 2010, the sensitivity coefficient of the water, grassland and desert kept rising in each terrain area, whereas woodland and cultivated land kept  declining. Based on the quantitative measurement of the terrain gradient effects of the ESV driven by landuse change, the spatial differentiation and its change of ESV with  the change of terrain gradient were clarified. The results can provide the theoretical basis for protecting regional ecosystem and rational use of land resources in the future.
Key words：land use; ecosystem service; topographic index; terrain gradient; the Upper Reaches of the Minjiang River; eastern edge of Tibetan plateau