The invention relates to an automatic classifying and identifying method of a road line point cloud based on three-dimensional laser reflection strength. The automatic classifying and identifying method comprises the following operation steps of acquiring point cloud data by utilizing a laser scanner, and calculating an equation of a POS plane of each scanning circle according to the attitude and position information of a POS system in each scanning circle of the point cloud data; calculating included angles between the connecting lines of three-dimensional coordinate points and the centers of the POS planes and the POS planes in the scanning circles, comparing the included angles with an angle threshold, and primarily judging the points larger than the angle threshold as pavement points; recalculating the distances from the primarily judged pavement points to the POS planes, in which the points are located, of the scanning circles, taking the height H of the POS system during the mounting as a known value, comparing difference values between the calculated distance values and a height value H, and taking the points smaller than the threshold as the pavement points; counting the strength values of the secondarily judged pavement points, and judging the points with the strength values larger than the threshold value as the road lines. The automatic classifying and identifying method has the advantages of rapidness, high efficiency, repetition in checking and convenience in error detection.