The invention discloses a system and method for wet flue gas desulfurization and oxidation monitoring in cooperation with sulfur mixing and blending combustion of a thermal power plant, and belongs to the technical field of sulfur mixing and blending combustion of thermal power plants. The system comprises an absorption tower for desulfurization reaction, an SO2 inlet pipe, a boiler and a slurry oxidation analyzer, wherein the SO2 inlet pipe is arranged on the outer side of the absorption tower, an SO2 outlet is formed in one side of the upper end of the absorption tower, and detection equipment is arranged at the SO2 outlet; the boiler is arranged at the upstream of the absorption tower, a flue gas channel of the boiler communicates with the SO2 inlet pipe, and a furnace coal quality analyzer is arranged at the upstream of the boiler; and the slurry oxidation analyzer is arranged at the downstream of the absorption tower. According to the system, the sulfur mixing and blending combustion function is integrally guided by desulfurization, so that the desulfurization potential is excavated to the maximum extent, the actual desulfurization maximum output is found out, the sulfur content of fire coal can be further increased from a design value and determined by a blending combustion experiment, the purchasing range of the coal coming market of a power plant is enlarged, the adaptability and diversity of the fire coal are improved, economic coal with higher sulfur content is purchased, and the power generation cost is greatly reduced.