Abstract: The critical point of carbon emission in processing pure grain liquor by solid fermentation is significant to find the key processes of carbon reduction, guiding enterprises to low-carbon processing. Based on the theory of Life Cycle Assessment, the carbon emissions in liquor processing was quantified and the critical points were locked through the contribution rate of carbon emissions in processes in this paper. Results showed that liquor steaming strongly attached to the coal-burning boiler, which was the most critical point of carbon emissions in liquor processes, while net electricity consumption and transport in the plant were both mainly contributed to the carbon emissions of processing. Therefore, the method was contributed to promoting the low carbon emission of the pure grain liquor processor, improving the energy consumption structure and processing pure grain liquor by taking the biomass and other clean energy. These results also provided a reference to reduce carbon emission in food processing.