Phase retrieval technology combines optics and calculations to recover phase from the intensity measurement, including transport of intensity equation and angular spectrum iterative. Unfortunately, the former is only effective for near-field phase retrieval, and it can not be directly applied to the phase retrieval of natural scenes, because this method is based on the assumption of coherent illumination. The latter has many shortcomings including iterative uncertainty, slow convergence and so on. Traditional transport of intensity equation combining with angular spectrum iterative is explored in the case of coherent illumination. The fusion method is further expanded and the phase retrieval method is proposed for natural scene lens model. The phase of the image plane is calculated using transport of intensity equation, and the value is used as the initial value of the angular spectrum iterative. The phase information in the object plane is acquired according to the reversibility of the optical path. The results of experiments are given in these two cases.