The Shangri-La County and its surrounding areas lie within the Hengduan Mountains system at the southwestern margin of the Tibetan Plateau, and belong to the core zone of Three Parallel Rivers of Yunnan Protected Areas. There are numerous snow mountains of special ecological and cultural significance. The investigation of snow cover dynamics is important for understanding how snow cover responds in the context of climate change. In this study, the spatial and temporal dynamics of snow cover in the entire area were analysed using 28-scene Landsat images from 1974-2012. Snow cover variability of different altitudinal zones and orientations was also discussed. Then, we explored the relationship between snow cover dynamics and both climate change and local tourism activities. The results show that snow cover area in the Shangri-La region continued a clear decreasing trend in the last 40 years, declining from 4188 km 2 in 1974 to 901 km 2 in 2012. The decrease of snow cover generally occurred from low to high altitude and was most pronounced at altitudes of 4000-5000 metres, with a reduction of 2800 km 2 since 1974. Snow cover decreased more significantly in the northwest part of the area than in the southeast. The primary driving force for this decrease was attributed to the increase in air temperature (+0.22°C per decade in the area). Compared with a similar decreasing trend in the Meili Snow Mountains, a dramatic reduction of snow cover in the southeastern Yulong Snow Mountains is attributed partially to local tourism activities.