Abstract: The studies on fix wing Unmanned Aerial Vehicle (UAV), especially, flying wing type has progressed very rapidly. Therefore, fix-wing UAV can be used to support disaster mitigation and monitoring. But in order to make UAV completes the mission, it needs an autonomus flight control system. There were two types of control method in order to control the movement of flying wing, i.e., longitudinal and lateral. Control of lateral motion is considered more important because it serves to prevent air turbulence that can cause the air to move is not in accordance with the mission that has been set. This research aims to design control lateral movement that is focused on using the roll rotational motion mode control method Linear Quadratic Regulator (LQR) with the addition of integral in dealing with steady state error that occurred. Experiments conducted by simulating the model airframe using DATCOM and control simulation using MATLAB. The results showed that by using modifeied LQR control with integral components added, the system is able to stabilize the rotational motion roll in a short time and minimal overshoot. In addition, the experiment also showed that steady-state error in the system can be eliminated with a rise time = 0.189 sec, overshoot = 0.688%, settling time = 0.301 sec and steady state error = 0%.