The invention discloses a multi-region load reduction collaborative decision-making method considering power grid risk levels and belongs to the power system and power system automation technical field. According to the method of the invention, on-line verification is performed according to a power grid load reduction off-line strategy and on the basis of a power grid actual operation mode, the load reduction risk level of each of regions is evaluated for the load reduction quantity of the regions on the basis of the 599 order; and as for regions of which the accident risk levels do not satisfy requirements, the load reduction quantity of the regions is distributed on the basis of comprehensive consideration of factors such as load reduction sensitivity, load importance degree and load adjustment cost, so that the load reduction quantity of the regions of which the accident risk levels do not the satisfy requirements is distributed to regions with high priorities and low safety accident risks, and therefore, power safety accident risk levels can be decreased or avoided. With the method of the invention adopted, the engineering application of a large power grid in safety and stability analysis and risk assessment can be greatly improved.