Mosquito are small insects, have three pairs of legs, two scaly wings, and a mouth (proboscis) to pierce and suck blood. Mosquito have various characteristics, especially in the morphology of the type of mosquito and their beneficial role for the ecosystem, namely as a food chain and their role that is detrimental to their host with their nature as a vector. This study aims to determine the biodiversity of mosquitoes and its prevalence in mountains ecosystems and beach in Luwu District. This type of research is a descriptive ecological study using an observational approach. The population and sample of the study were all mosquitoes and mosquitoes caught in the villages of Siteba, Limbong, Sangtandung as a mountains ecosystem and Bonepute, Temboe, Babang villages as a beach ecosystem in Luwu District. Data were obtained using the Animal Baited Trap, Human Landing Collection and Light Trap methods, then identification was carried out at the Entomology Laboratory, Faculty of Medicine, Hasanuddin University. The results of research in the mountain ecosystem of mosquito biodiversity obtained four genera, namely Anopheles, Aedes, Armigeres and Culex. Beach ecosystems are found in three genera Anopheles, Aedes and Culex. The density of mosquito in the mountains is more dominant, namely Cx.Tritaeniorhyncus, bait for people in the house 4.03 mosquito / person / night and bait people outside the house 4.39 mosquito / person / night. The more dominant biting beach ecosystem is Cx.Tritaeniorhynchus. Insider bait 3.47 mosquitos / person / night, bait outside the house 6.19 mosquito / person / night. The effectiveness of mountain traps obtained 14 species, beach 11 species. Further research is needed in depth information about the distribution patterns of mosquito fauna and their intensiveness in the mountains and beach ecosystems of Luwu District.