A power generation scheme based on biomass integrated gasification combined cycle (BIGCC) has emerged as a potentially high-efficiency and environmentally friendly power system. However, a life cycle assessment (LCA) of BIGCC systems with different technology options has not been performed to date. This study provides LCA of eight BIGCC systems, which examines technical alternatives of biomass gasification, syngas combustion, and CO₂ emission control. This study uses OpenLCA software according to the CML (Center of Environmental Science of Leiden University) 2015 impact assessment method. Results show BIGCC systems’ global warming potential (GWP) is lower than 240 kg CO₂-eq/MWh, which is negative when BIGCC systems integrate with CO₂ capture and storage technology. Furthermore, the external syngas combustion method has lower GWP, human toxicity potential, and ozone depletion potential than the internal syngas combustion technology, and the Selexol CO₂ capture process is cleaner than the MEA CO₂ capture method. Moreover, sensitivity analysis illustrates plant construction and energy efficiency have larger impacts on the environmental indicators of BIGCC plants than other parameters. Finally, uncertainty analysis indicates that BIGCC systems have a high potential to reduce the emissions from the mixed electricity grid of European Union of 27 Member States (EU27).