The invention discloses combined laser tracking and inertial surveying system for measuring position and gesture of space object composed of inertial surveying subsystem, laser tracking measurement subsystem, and computer control and data collection and process subsystem connected to the above said two systems. The invention is also discloses a dynamic tracking measuring method. Based on requirement of Kalman filtering algorithm, the method builds system equation and observation equation for moving target between fixed connected coordinate system and global coordinate, and edits expanded Kalman filtering algorithm for optimal modifying each error information. So as to calculate out information of position and gesture of target in fixed connected coordinate system related to global coordinate. The invention raises stability and measuring precision, and enriches output information measured.