The coal-to-methanol process consumes non-renewable resources, causing significant negative environmental impacts. Introducing renewable biomass to replace or partially substitute coal is a highly feasible way to improve the process. This research not only delves into biomass utilization but also undertakes a comprehensive analysis of elemental and energy utilization efficiency, alongside a "cradle to gate" life cycle assessment for the methanol production process via coal and biomass co-gasification. CML and ReCiPe methods are applied to investigate the damages of the processes with different raw material compositions to source efficiency, environment, and human health, meanwhile exploring insights for process enhancement. Findings reveal that adding biomass positively influences, while, the amount of biomass added should be optimized to achieve the best performance. The energy efficiency and O utilization efficiency peak at 50% biomass ratio, whereas C and H utilization efficiency improve as the biomass content increases. Biomass addition notably mitigates the ecological, human health, and resource depletion impacts of the production process. Significantly, a biomass ratio of 30%-50% is recommended for the most substantial improvement in methanol production compared to the coal-only route. Within the lifecycle's various stages, biomass growth exerts the most substantial impact on the assessment indices, indicating the pivotal role of biomass as both a challenge and an opportunity in optimizing the environmental footprint of methanol production processes.