The invention provides a power grid aggregation model construction method, and the method comprises the following steps: a power grid is partitioned; and load model aggregation, tie-line model aggregation and power supply model aggregation are performed in every power grid area. According to the invention and the above steps, the simplify processing of the target power grid is realized; the complexity of the power grid is greatly reduced based on keeping operating characteristics of the power grid in prior art; and the calculating speed can be greatly improved in new energy accommodating capability calculation.