The invention provides a distributed photovoltaic power load permeability estimating method and a distributed photovoltaic power load permeability estimating method. The method comprises the following steps: fitting a main grid load characteristic curve and a distributed photovoltaic generation power characteristic curve under different types of weather to get an explicit expression of the main grid load characteristic curve and the photovoltaic generation power; calculating the theoretical value of electricity sales and the theoretical value of distributed photovoltaic generation capacity under different types of weather and in different time periods through an area integral method; and calculating the distributed photovoltaic load permeability of a sunny day or in a preset time period of a sunny day according to the number of sunny days, the electricity sales and the quantity of distributed photovoltaic self-generated and self-supplied electricity in a month to be calculated, and thus getting finer-dimensional distributed photovoltaic power load permeability. The influence of distributed photovoltaic on the grid load under different types of weather and in different time periods is better reflected. Power companies are enabled to accurately assess the influence of distributed photovoltaic on the load operation of the main grid, and thus, stable operation of the grid is promoted.