In view of the existing problems in the formation of dual-wheeled mobile robots under three-dimensional environment, an obstacle avoidance multi-robot formation algorithm, based on methods of fictitious navigation and backstepping, and combined with the artificial potential field method, has thus been proposed. First, an analysis has been made of the formation model of the multi-robot system in three-dimensional environment, followed by an analysis of the spatial projection of the model onto a two-dimensional plane. Second, the kinematics model will be transformed into a chained form, where the error system will be transformed into a series nonlinear system through a canonical coordinate transformation. Third, Lyapunov function of the wheeled robot tracking system will be constructed by using backstepping method and a design of the trajectory tracking controller for wheeled robots will be obtained. The multi-robot formation in complicated environments, combined with the artificial potential field obstacle avoidance strategy, will be accomplished. Finally, the effectiveness of the proposed method will be verified by two groups of simulation experiments of multi-robot trajectory tracking.