The requirement of the accurate pedestrian position is increasing due to the booming pedestrian-to-vehicle (P2V) communication. Currently, global navigation satellite system (GNSS) receivers can provide accurate and reliable positioning service in open-field areas. However, its performance in city downtown is still affected by the multipath and none-line-of-sight (NLOS) receptions. This paper proposes an innovative positioning method using the 3D building maps and the receiver autonomous integrity monitoring (RAIM) satellite selection method to achieve satisfactory positioning performance in urban area for the pedestrian user. The 3D building model is used with a ray-tracing technique to simulate the line-of-sight (LOS) and NLOS signal travel distance, which is well-known as pseudorange, between the satellite and receiver. The proposed RAIM fault exclusion is able to compare the similarity between the raw pseudorange measurement and the simulated pseudorange. The measurement of the satellite will be excluded if the simulated and raw pseudorange is inconsistent. Because of the assumption of single reflection in the ray-tracing technique, the inconsistent case indicates it is a double or multiple reflected NLOS signal. According to the experiment result, the RAIM satellite selection technique can reduce about 8.4% of the large positioning solutions (points that estimated at the wrong side of the road) in the middle urban canyon environment.