To detect the depth, area and volume of potholes automatically, three test bodies with different sizes were scanned by 3D line laser technology. TIN plane interpolation method was employed to reconstruct the 3D laser-point cloud data model, and a combination of contour line pick-up algorithm was used to calculate multi-dimension indexes of potholes. The ASTM experimental criteria was adopted to verify the validity of index calculating method, and the error rules of depth, area and volume indexes of potholes in different sizes were analyzed. Results show that the maximum relative errors of depth, area and volume of potholes were 4.60%, 3.87% and 10.82%, respectively, and the relative errors of depth and area decrease with increasing of potholes sizes. Accurate detection of multi-dimension index of potholes could be achieved with utilization of line laser technology, and this proposed method could provide the basis for fast and accurate judgement of severity of potholes, determination of damage level and estimation of repair materials.