A nonlinear phase shift test method of high power laser facility based on enumeration thought is proposed for no-chirp laser pulse. Combined with the pulse waveform and the variation of energy flow, the theoretical distribution of broadening spectrum after pulse amplification is obtained under different nonlinear phase shift hypotheses. The theoretical distributions of the broadening spectra are compared with the measured ones. Then hypothetical values of the nonlinear phase shifts corresponding to the theoretical broadening spectra are the results of the measurements when the residuals are the minimum. This technique and method are not limited by the pulse time waveform,which effectively improve the confidence of the measurement results.