The invention belongs to the technical field of power grid overall measurement and calculation, and provides a method for judging power grid investment optimization, which comprises the following steps of: judging historical data extrapolation; calculating key factors influencing the total investment scale of the power grid; and calculating a multi-scenario input scale calculation total factor. Byusing the method provided by the invention, the investment scale can be accurately measured and calculated, reliable data can be given, and comprehensive prediction of the investment scale of a powergrid enterprise is facilitated.