The basic principle and characteristics of a new kind of linear phase-retrieval (LPR) wave front measuring method were analyzed. A far-field image of the LPR sensor system itself should be measured and stored as the image of calibration in advance. The difference between an image of aberration and the image of calibration was measured using the LPR sensor, then the Zernike coefficients of aberration was gotten by calculation method of linear matrix multiplication. The process and method to get Zernike reconstruction matrix were discussed. The performances of the LPR method was tested by numerical simulation on measuring atmosphere disturbed wave front using the LPR method. The results showed that the LPR obtain high spatial resolution, and high precision for small aberrations, but the measuring range is limited. Therefore the LPR is suitable for close-loop adaptive optics systems.