Abstract: In order to improve the performance of lane detection for curve road, a lane detection system was presented with a linear approximation method. Based on the priori knowledge of lane geometry, some initial edge points of the lane were extracted through inverse perspective mapping and Hough transformation. Considering the initial results, a method of linear approximation was applied to search the future lane edge points. Finally, the detected points were used to rebuild the lane according to a B-spline model using least square method. Test of this system shows a promising detection result for curve lanes.