Based on the Lyapunov stability theory and the fractional-order system stability theory, an active feedback control method using neural networks and disturbance observer is proposed for the robust synchronization of a class of different fractional-order chaotic systems with uncertainties. The disturbance observer is designed to observe the disturbance, and the disturbance that is not observed is compensated by sliding mode control. Finally, the synchronization of fractional-order chaotic systems is realized. Compared with the existed methods, the adopted models in the proposed approach are more in line with engineering practice, and the upper bounds of the uncertainties are not required. Numerical simulations verify the effectiveness of the proposed method.