Abstract: A diffraction tomography reconstruction algorithm is established based on Distorted Born Iteration (DBI). In the iteration, the well-posed forward scattering equations for an estimated total field and ill-posed inverse scattering equations for the desired object property function must be alternately solved to process the nonlinear property of ultrasound inverse scattering image.The regularization method is used for the ill-posed inverse scattering equations,and this makes the iterative convergence to the true solution of the problem for objects with high contrast.The ill-posed problem is analyzed by Picard theory and the method is proposed for analyzing the degree of contantination of the model by noise and the application conditions of regularization. In the experiments, the reconstructed image has acceptable visual quality in simulating image reconstruction.