The invention relates to a high-proportion external-region electric power and in-province power supply collaborative absorption dispatching operation mechanism used for planning power supply generating capacity in and outside a province as a whole, on the basis of researching the current situation of electric power from external regions, knowing external-region electric power planning interconnected with the province and in-province power supply planning and mastering a proportion of electric power from external regions and an electric power balance situation, a grey correlation analysis method is adopted to research influence of external-region electric power on coordinated operation of power supply in and outside the province, and according to an association degree index, an upper-level and lower-level dispatching coordinated operation mechanism, an in-province and outside-province power supply benefit sharing mechanism, an in-province and outside-province power supply regulation obligation allocation mechanism, a trans-regional trans-provincial auxiliary service compensation mechanism and an adjacent province and city power grid standby sharing and accident support mechanism. Through establishment of the dispatching operation mechanism considering high-proportion external-region electric power and in-province power supply collaborative absorption, the activeness and enthusiasm of in-province and outside-province power supply in participating in power grid regulation are mobilized, and safe, high-quality and economical operation of a power grid in the province is guaranteed.