Neural network(NN) research has gone a long way in the past decade. The specialists in the image processing field have fully understood the advantages of neural network techniques such as the abilities of parallel computing, nonlinear mapping and self-adaptiveness, and applied a variety of neural network models into the image processing field. In this paper, we review many applications of neural network in image processing and discuss the present and future of neural network. All these applications are categorized according to the phases of image processing and discussed in detail. In conclusion of this paper, we list several disadvantages of neural network techniques, and bring forward the prospect of neural network techniques in the image processing field.