Biomass estimation is important to understand the benefits of vegetation in the urban area. Since administratively separated from Tangerang Regency in 2008, the population increased substantially by approximately 3.64%. The rapid urban expansion tends to prioritize a short-term development and led to the conversion of green areas to urban uses. Moreover, it will reduce the vegetation cover which is important in reducing carbon emission. This study used field - sampling measurement and vegetation indices formula to develop a simple biomass estimation model. This study aims to estimate biomass values, the amount of CO2 stored by vegetation and also explain the spatial distribution of biomass in South Tangerang. The allometric equation developed by the United States Department of Agriculture (USDA) is used to get the biomass value from field measurement data. Vegetation indices formula includes NDVI (Normalized Differential Vegetation Index), SAVI (Soil-adjusted Vegetation Index) and ARVI (Atmospherically Resistant Vegetation Index) extracted from the SPOT-7 image. Grid analysis used for analyzing the data.