For unstructured road image, a road detection and intelligent warning algorithm is proposed based on vanishing point information. Segmentation algorithm firstly employed the straight line information, vertical envelope, grouping strategy and path clustering algorithm to estimate the vanishing point. Then soft voting method is proposed to extract road region based on the boundaries and vanishing point information features. Finally, according to the features of unstructured road region, the navigation line is extracted, and yaw distance and yaw time warning decisions are depended on the vehicle yaw Angle. Thus, the intelligent lane departure warning algorithm can be achieved. Experimental results show that the proposed algorithm can quickly and efficiently extract the road region of unstructured road. At the same time, the algorithm can be effective for lane departure warning according to early warning parameters.