This study aims to assess the diversity of butterflies (Lepidoptera: Rhopalocera) at the location of the PT Pertamina Geothermal Energy (PGE) Lumut Balai Geothermal powerplant, Muara Enim, South Sumatra. This rapid survey was carried out on 4-15 June 2023, taking place in 7 locations namely Cluster 5, Cluster 6, Cluster 7, Cluster 9, Cluster 10, APL 17 and APL 18. The method used is the direct observation method by walking along a 1000 meter transect line (Yustian et al., 2017) in each type of habitat (secondary forest, mixed shrub secondary forest, coffee plantation , open areas and secondary forests near to rivers/water sources). The results obtained in this rapid survey are that there are 5 butterfly families consisting of Papilionidae, Pieridae, Nymphalidae, Hesperiidae and Lycaenidae with a total of 51 species and 254 individuals. The highest diversity index based on Shannon's diversity index and Margaleff's species richness index is in APL 17 with a secondary forest habitat type near to coffee plantations (H'=3.14, R=7.08) and the lowest is in Cluster 9 (H'=2.11, R=3.23) which is a secondary forest near to a geothermal power plant. Meanwhile, the highest evenness index was found in APL 17 (E=0.97) and the lowest in Cluster 7 (E=0.87) with a riparian habitat type. During the research, protected species were recorded, namely Troidesamphrysus and Troideshelena.