The invention provides a phase shifter mounting place selection method based on system power flow entropy. The method comprises steps that, different mounting places of a phase shifter are determined; power flow distribution of different mounting places of the phase shifter is determined; a line load rate, a line importance degree and a system power flow entropy of an AC line are calculated; the final mounting place of the phase shifter is determined. Through the method, various indexes of a power transmission channel transmission power distribution ratio, a line load rate and a power flow balancing degree can be integrated, so a technician is facilitated to conveniently select the mounting place of the phase shifter and a shift of a phase shift angle, and the phase shifter can be effectively utilized to realize power flow distribution balancing.