Abstract: Purpose: Review different methods in medical image registration.Method: Parametric and non-parametric registration methods. Result: Various registration methods and applications are presented. Conclusion: Different registration methods fit to different kinds of medical images and result different applications in medical field. In medical field, researchers need to combine and compare the information given by functional and anatomical images. For the reason, image registration which can map points from one image to homologous points on an object in the second image is one of the fundamental tasks in image processing. Different numerical methods are introduced into registration due to the different images taken from different perspectives, times and devices. In this paper, we present an overview of recent methods for image registration in medical field. We start by the goal of image registration and introduce the framework of a registration process. The registration methods under review are classified into two categories: parametric image registration and non-parametric image registration. Typical methods in each category are presented. In each case, we provide the readers with general background information and properties or explanation of how these methods work.