Abstract: The principal construction of wave-front sensor developed from the linear phase retrieval algorithm is described in this paper. In the laboratory, an experiment device was set up to study the characteristic of the new wave-front measuring method using this kind of sensor. The real time intensity in focus was measured，and then the incident wave-front phase was easily recovered using the approximately linear relationship between the little change of focus intensity and the little change of phase. The sensor can do comparatively precise measurement on the aberration of defocus，astigmatism and so on, with error rates less than 1. It doesn't influence the veracity of recovered results much even if there exists a small unsymmetrical aberration in the aberration of the symmetrical system.