Salvia L. (Lamiaceae) is a worldwide genus with rich species diversity, a variety of habitat types and unique pollination mode. Previous studies have focused on flower structure and ecological function of stamen lever mechanism, the evolutionary response of stamen lever mechanism to spatial variation in pollinators and phenotypic selection of Salvia. However, the pollinator's compositions, behavior and reproductive success of representative Salvia species distributed in different flora have been rarely studied. We studied the pollination ecology, breeding system and reproductive characteristics of Salvia castanea, which is widely distributed from the eastern Himalayas to the Hengduan Mountains, we analyzed the composition of pollinators and the interannual changes of pollinator behavior from 2014 to 2016, the daily changes between sunny and rainy days in 2014, and discussed their effects on the reproduction. The results showed that a total of 9 species of visiting insects were found in Salvia castanea during three years and the change of pollinator's composition and their behavior was obvious. In 2014, S. castanea was legitimately visited by four species including Bombus friseanus, B. grahami, B. religiosus, and Apis cerana. In 2015, the pollinators were reduced to only one species, B. friseanus, however, in 2016, there were two legitimate pollinators, B. grahami and B. religiosus. The nectar robbery is common in S. castanea, and the main robbers are B. grahami and B. friseanus. We found that visiting behavior of B. friseanus showed inter-annual variation and was largely affected by climate, while the nectar robbery of B. grahami probably was affected by activities of B. friseanus. The breeding system for S. castanea was obligate outcrossing, which mainly depended on pollinators for seed set. In the absence of pollinators, low degree of autonomous selfing can provide reproductive assurance for S. castanea, and there was no pollen-limitation and inbreeding depression. Our results revealed that in alpine regions, climate was changeable and weather conditions significantly affected composition of pollinators visit behavior and pollination efficiency, which might, in turn affect reproductive success and population stability of plants. Legitimately, visitation rate is the main factor for ensuring high seed set of S. castanea in open pollination condition, and nectar robbery could maintain a neutral effect on reproductive success at a certain level. Our results of this study provide valuable insights for illustrating how the reproduction of alpine Salvia species is affected by climate and environmental changes and reproductive strategies to ensure reproductive success.