This paper focused on the environmental performance of a nearly zero-energy wood-based educational building (NZEB-W) via the life cycle impact assessment (LCIA). It identifies the environmental impacts of construction materials and operational energy demands of the NZEB-W and compares them using the SimaPro 8 software with the IMPACT 2002+ method. The LCIA results from NZEB-W show that the overall environmental impact of construction materials (98.9 Pt) and 45 years operational energy demands (98.6 Pt) will be at the same level. Its overall environmental impact 197.75 Pt for 45 years is relatively small. NZEB-W has the greatest impact on the environment in the category of damage respiratory inorganics (34.5%), 419 kg PM2.5 eq from construction materials, and 271 kg PM2.5 eq from operational energy for 45 years; follows global warming (31.7%), 1.98 × 105 kg CO2 eq from construction materials, and 4.23 × 105 kg CO2 eq from operational energy for 45 years; and non-renewable energy (21.8%), 2.82 × 106 MJ primary from construction materials, and 3.73 × 106 MJ primary from operational energy for 45 years. As this environmental assessment shows, the material composition of construction materials compared to the energy consumption in the use phase is an essential element for understanding the life cycle impact of buildings.