Ecotourism is regarded as one of the most effective ways to solve the conflict between conservation and community development. However, there are rare discussions on how much ecotourism progress will affect wildlife. To explore whether tourists' noise during ecotourism activities affect Black Snub-nosed Monkeys (Rinopithecus bieti) during ecotourism activities, we record tourists' noise value and viewing distance, tourists number, monkeys’ behaviour, the total number of visible monkeys and the number of monkeys in different age-sex groups by 10-minute instantaneous scanning sampling method from July 5, 2017, to February 8, 2018, in Yunan Shangri-La Yunnan Golden Monkey National Park. The results show that ecotourism significantly increased the environmental noise value, which the noise value (52.42 dB) in the tourist open period was significantly higher than that (47.51 dB) in the non-open period, and the noise value is positively correlated with the number of tourists, and negatively correlated with the viewing distance and the number of visible Black Snub-nosed monkeys (Table 2); There were significant differences in the number of visible Black Snub-nosed monkeys at different viewing distances, and the number reached a maximum (2 046 ind) at the viewing distance of 11﹣15 m. Within the ornamental distance of 1﹣5 m, the resistance ability to the interference of varying age groups was significantly different, and the adult males have the most robust stance ability, followed by adolescent individuals. This study suggests that the ecotourism process in Shangri-La Yunnan Golden Monkey National Park has increased the environmental noise value and disturbed the Black Snub-nosed monkeys. Short tourists' viewing distance and the number of tourists increased disturbance degree. We suggest that the viewing distance of tourists should be strictly limited in the future ecotourism process, with the standard of more than 10 m; slogans should be set up to remind tourists to keep quiet to reduce the disturbance.