A method and apparatus for controlling a vehicle in an autonomous driving system. The method for controlling a vehicle in an autonomous driving system can improve recognition accuracy of an object by outputting light corresponding to a first brightness value changed in correspondence to detection of an object having a recognition error larger than a predetermined range during driving while outputting light corresponding to a first brightness value that is determined of the basis of information about external illumination. An autonomous vehicle of the present disclosure may be associated with an artificial intelligence module, a drone ((Unmanned Aerial Vehicle, UAV), a robot, an AR (Augmented Reality) device, a VR (Virtual Reality) device, a device associated with 5G services, etc.