The invention relates to a method and system for dividing a power grid development period based on multiple evaluation indexes. The method is characterized in that the method comprises the following steps of (1) acquiring power grid original data including evaluation indexes, wherein the power grid original data includes historical data of per capita power consumption quantity, per capita power generation quantity, per capita household electricity consumption quantity and per capita renewable energy power generation capacity evaluation indexes of a nation, (2) using a principal component analysis method to process the power grid original data to obtain a power grid development index, (3) using a curve to fit the power grid development index, and (4) dividing the development process of thepower grid development index into different development periods through the geometric characteristics of the curve. According to the method and the system, the power grid is safer and more economic, deficiencies in quantitative division in the development period of a national power grid can be made up, and a reference basis is provided for the development planning of the power grid and power gridinvestment.