The spatial attitude of six-wheeled rocker rover constantly changes when it crosses complex terrains or obstacles. In order to model the spatial attitude of the rover, the structure of the rover was simplified and summarized. Five spatial parameters of the rover were defined (the parameters include the inclination angles between differential shaft and level ground, rotation angles of main and sub rockers) and the center height of six wheels was involved in the model as terrain parameters. Finally, the mathematical model of the spatial attitude of the rover was established, based on which the forward solution and inverse solution were defined and corresponding solutions were proposed. This research provides the basis for the performance analysis of the six-wheeled rocker rover in different aspects.