The disclosure discloses a method for detecting a vehicle in a driving assisting system. The method for detecting a vehicle in a driving assisting system includes: obtaining an image to be detected, and determining the positions of lane lines in the image to be detected; determining a valid area in the image to be detected, according to the positions of the lane lines, and the velocity of the present vehicle; and determining a detected vehicle in the valid area according to T preset weak classifiers, and thresholds corresponding to the respective weak classifiers, wherein T is a positive integer.