HHD maps (high definition maps) with high accuracy of object locations are essential for self-driving cars. With an HD map, the localization software can figure out where exactly the car is located. In addition, semantic map can provide more valuable information, ex: road boundary, traffic lanes, road signs, intersections, the speed limit on this road, the location of pedestrian crossings and parking spaces, etc. All information can be integrated with data from sensor, and makes driving more safe and comfortable. Semantic map is contained inside the HD map. To build a semantic map, AI plays an important role to classify objects from image and 3D data.