The invention relates to a coal-fired coupled biomass power generation system and method, and belongs to the technical field of biomass energy. The system comprises a biomass pyrolysis unit, a storageprocessing unit, a pressurized gasification unit and a coal-fired power generation unit. The method comprises the following steps: firstly, biomass raw materials are pyrolyzed and converted into bio-oil and pyrolytic carbon nearby, and then the bio-oil and the pyrolytic carbon are processed into bio-oil slurry and organic acid calcium; and the bio-oil slurry generates high-temperature fuel gas byutilizing a pressurized gasification furnace, and the high-temperature fuel gas is directly sent into a coal-fired boiler for co-combustion power generation. According to the method, efficient conversion and utilization of waste resources such as biomass and sludge are achieved, the scale requirement for coupling biomass power generation in a large coal-fired power plant can be met, meanwhile, the carbon product with the high additional value is co-produced, the organic acid calcium can be further used for desulfurization and denitrification in a circulating fluidized bed boiler, and the system and the method have good application prospects.