Remote subalpine wetlands are subjected to limited human direct disturbances, and hence they are ideal sites for tracking the combined effects of climate change and atmospheric deposition on wetland ecosystem evolution. This study investigated environmental changes in Congping Wetland located in the Wushan Mountains during the past 200 years, based on the ²¹⁰Pb and ¹³⁷Cs chronology, subfossil chironomids and element contents of a 50 cm long sediment core collected from the wetland. The results revealed that chironomid communities were dominated by Chironomus anthracinus-type, Limnophyes sp. and Cladotanytarsus mancus-type 1 before 1910, and then they were characterized by the co-dominance of C. mancus-type 1, C. anthracinus-type, Procladius sp. and Endochironomus impar-type between 1910 and 1925. All the dominant species mentioned above are adapted to shallow water environment. Thereafter, nutrient-tolerant species, including E. impar-type, Polypedilum nubeculosum-type and C. anthracinus-type became the dominant taxa. Redundancy analyses indicated that total phosphorus, total carbon and Ca were significant environmental variables explaining variance in chironomid data. Chironomid communities before the 1930s might be linked to low runoff input and shallow water table in this wetland, while changes in the communities after the mid-20th century mirrored nutrient enrichment due to intensified atmospheric deposition. Under the combined effect of atmospheric deposition and climate change, the increase of nutrient-tolerant species and biodiversity loss indicate that Congping Wetland is facing with ecological environment degradation.