The conventional mirror stabilized platform consists of two-axis azimuth-elevation gimbal axes and the sensor input Line-of-sight (LOS) is always oriented parallel to the outer gimbal axis. Compared with conventional mirror platform, the bias shafting mirror gimbal axis can have an arbitrary orientation with respect to the sensor LOS, and the resulting LOS kinematics are both axis-coupled and non-linear. The primary purpose of this paper is to study LOS kinematics and dynamic modeling of this bias shafting mirror. Firstly, the artificial mass stabilization platform method was proposed to derive LOS kinematics. Meanwhile, the artificial platform gimbal type was determined to derive equations of dynamics. And a complete dynamics model was presented based on LOS coordinate system. Then, the carrier motion coupling was analyzed and system control block diagrams were developed. Lastly, simulation results show that the characteristics of LOS pointing and torque coupling is different between the bias shafting and conventional mirror platform.