The invention relates to a method and a device for configuring and optimizing a micro energy grid energy supply system. The method comprises the following steps: determining the annual profits of theconfiguration schemes of the micro energy grid energy supply system according to the annual heat and power load predicted values and annual energy output predicted values of the configuration schemesof the micro energy grid energy supply system; further determining the engineering age limit gross profits of the configuration schemes of the micro energy grid energy supply system according to the annual profits of the configuration schemes; and selecting the optimal configuration scheme of the micro energy grid energy supply system according to the engineering age limit gross profit of each configuration scheme. Through the technical scheme, the reasonable configuration scheme is selected based on the economical analysis results of the different configuration schemes, the problem of excessive cost or resource waste caused by unreasonable configuration is avoided, and simultaneously, safe and stable operation of a distributed power grid system is promoted.