Mobile CARM is a more and more important device for spine surgery navigation. The accuracy of the intraoperative image has a huge influence on the surgery success rate. For the purposes to achieve the surgery, the image capture device should be modeled by an accurate method. This paper describes the problems of establishing the CARM model. By analysis the structure of the mobile CARM, we establish the static model of the CARM. Next by kinematics analysis, we establish the dynamic model which could guarantee the accuracy of the CARM. Last we confirm the deviation of CARM images.