As a bioindicator of soil quality and controller of soil dynamic (fertility), soil fauna is influenced by various environmental factors like climate and edaphic elements. This research aimed to examine the abundance of soil fauna in a lower montane forest ecosystem at different elevations and analysed how the environment affects their abudance. The study used purposive sampling in Gunung Halimun Salak National Park, specifically at altitude of 1,100 masl; 1,200 masl; 1,300 masl; and an open area (1,230 masl) as a control. LSD test revealed a significant difference on soil fauna abundance between the 1,100 masl elevation and the control group. However, there was no significant difference of soil fauna abundance between altitude of 1,200 masl and 1,300 masl. The highest abundance of soil fauna was found at 1,100 masl, with 156 individual/m2. Conversely, the lowest abundance of soil fauna was recorded in the open area at 1,230 masl, with 3 individual/m2. The Pearson correlation analysis showed that soil fauna had positive correlation with light intensity and air temperature, and negative correlation with air humidity. Furthermore, Soil fauna abundance had also positive correlation with edaphic parameters (CEC, C-org., litter weight, soil respiration, porosity, and soil temperature, except soil pH and bulk density.