The measurement precision of charge coupled device (CCD) is the main factor affecting the accuracy of wavefront reconstruction. Due to the limitations of camera manufacturing technology and environmental impact, it is inevitable that noise data will be collected, which will affect the image information collection with low signal-to-noise-ratio and high spatial frequency. An improved phase diversity wavefront sensor based on image compensation is proposed to reduce the influence of noise on wavefront reconstruction. First, two images are collected under the normal exposure time and saturated exposure time of CCD respectively. And then they are sewed into an image containing accurate high spatial frequency and low spatial frequency light intensity information. At the same signal-to-noise ratio, the improved phase diversity wavefront sensor and the traditional phase diversity wavefront sensor are simulated. The results show that the wavefront inversion accuracy of the improved phase difference wavefront sensor is significantly improved. Finally, the effectiveness of the method is further verified through experiments.