X4-AUV is a type of an autonomous underwater vehicle (AUV) which has 4 inputs with six degrees of freedoms (6-DOFs) in motion and is classified under an underactuated system. Controlling an underactuated system is difficult tasks because of the highly nonlinear dynamic, uncertainties in hydrodynamics behaviour and mostly those systems fails to satisfy Brockett’s Theorem. It usually required nonlinear control technique and this paper proposed an integral backstepping controller for stabilizing an underactuated X4-AUV. A control law is designed for the system in new state space using integral backstepping. The performance of the proposed control method is examined through simulation and results demonstrate all motion is stabilized and convergence into desired point. We also compared the results with backstepping approach to see the effectiveness of the propose control system.