The present invention discloses a system for detecting an obstacle for a vehicle. The system includes an information collection unit that monitors movement information of a vehicle, road information, and location information of the vehicle; a determination unit that determines whether the vehicle enters a special mode in which the vehicle turns and moves backward on a road through the movement information of the vehicle, the road information, and the location information of the vehicle from the information collection unit; and a controller that deactivates a rear monitoring function of either side of the vehicle in response to a determination that the vehicle enters the special mode.