This paper presents the orientation control of a differential mobile robot through the synchronization of the motions of two driving wheels, using an adaptive coupling control algorithm. The orientation error is usually caused by the synchronization error between two driving wheels and has the largest impact on the motion accuracy. The proposed controller incorporates the cross-coupling technology into an adaptive control architecture and guarantees asymptotic convergence to zero of the position tracking errors of two wheels as well as the synchronization error between them. Experiments demonstrate that the proposed control method exhibits better motion performance than traditional control methods especially in the orientation control.