Temperate glaciers are more sensitive to climate change than are polar or continental glaciers, and can drive remarkable runoff variation in local water catchments. Changes in the glacier area and surface elevation of the three monsoonal temperate glaciers in the Gongga Mountains, China, were analyzed using series of remote sensing images and digital elevation model (DEM) data. All possible sources of uncertainty were considered in detail. The results showed that the total glacier area decreased by 4.3 km² (6.7%) between 1966 and 2010. A comparison of glacier surface elevations using DEMs derived from dual-frequency differential GPS (DGPS) surveys in 2010, and from 1966 to 1989 from topographic maps. The three glaciers underwent significant mass loss from 1966 to 2010 and the mean surface elevation changes were −0.90 ± 0.45 m/y, −1.06 ± 0.45 m/y, and −1.12 ± 0.45 m/y for Hailuogou (HLG), Dagongba (DGB) and Yanzigou (YZG) Glaciers, respectively, from 1966 to 2010. Analysis of the meteorological data showed that the mean annual air temperature increase was the main reason for the thinning and volume loss. Thinning of the glacier tongue and volume loss was more intense in the period 1989–2010 than in 1966–89. Debris thickness and other factors are also believed to play important roles in differential thinning among different areas and periods.