Disclosed herein is an obstacle warning method for a vehicle, which includes detecting a first obstacle through a laser sensor, identifying a location of an adjacent vehicle, determining a blind spot of the adjacent vehicle due to the first obstacle based on the location of the adjacent vehicle, detecting a second obstacle involved in the blind spot through the laser sensor, and transmitting a danger message to the adjacent vehicle. A vehicle to which the disclosure is applied may be connected to any artificial intelligence (AI) module, a drone, an unmanned aerial vehicle, a robot, an augmented reality (AR) module, a virtual reality (VR) module, a 5th generation (5G) mobile communication device, and so on.