Butterfly is an important indicator of ecological quality and environmental change. Finding out the butterfly resources and their dynamics in Longqishan National Nature Reserve in Fujian Province is of great significance to the conservation and research of Longqishan biodiversity. We analyzed the butterfly diversity, population dynamics, and faunal composition throughout the nature reserve using Shannon-wiener index and relative abundance and continuous observations over a three year period (2016-2018). We recorded five families, 107 genera, and 193 species of butterflies in the Longqishan Nature Reserve. Among the six sample lines in the Longqi Mountains area surveyed, the greatest number of genera and species was recorded on the Xiaopei sample line, with 48 genera and 58 species recorded in total. Six recorded butterfly species are under state protection. Overall, the faunal composition was dominated by Oriental species (79.3%) followed by widespread species (21.2%). The dominant butterfly species composition did not vary significantly between years. The continuously stable, dominant species recorded was Ypthima baldus.