The traditional power measurement algorithm based on DFT needs to obtain the phase and amplitude of the current fundamental wave vector according to the result of current’s DFT, and then the operation would be performed according to the phase and amplitude of the phasevoltage fundamental wave vector obtained in phaselocked loop.Introduce a simplified power measurement algorithm. The real part and imaginary part of the current DFT’s resultcan be used with the phase voltage amplitude to get the active power and reactive power by selecting proper starting point of DFT, which would reduce the amount of calculation and the pressure of DSP. The algorithm was simulated through Simulink software. The compare ofresults obtained by simulation and theoretical calculation proved the feasibility and availability of the algorithm.