The invention relates to a low-temperature multi-effect seawater desalting multi-stage superposed adjusting raw water supply system which comprises a plurality of evaporators connected in series, adopts a multi-stage water supply mode, and is provided with multi-stage water supply mains, wherein one communication device is arranged between adjacent raw water supply mains to adjust water supply amounts among different raw water supply mains, the raw water supply amount of each stage except for the last stage is the optimal raw water spray amount of each effect, and the total raw water supply amount of the last stage is more than the sum of the required raw water amount of each effect of this stage. When the raw water supply amount of each stage is less than the optimal required raw water amount of all effects of this stage, the raw water supply main of the next stage adjusts the supply to the water supply main of the previous stage. By using the technical scheme of the invention, the ultimate discharge concentration of saline water can be controlled.