Abstract: The Satellite Based Augmentation System (SBAS) uses the pseudorange measurement corrections to enhance the integrity of navigation satellites, the code noise and multipath error processing accuracy are important factors affecting the service performance of the system and the accuracy of user positioning. In this paper, three different methods for dealing with raw pseudorange code noise and multipath error are introduced, including the single-frequency smoothing method, the code noise and multi-path correction (CNMC), and the code noise multipath method (CNMP) used by the Wide Area Augmentation System (WAAS). Through the data of the satellite-based augmentation system in operation, the influence of different code noise multipath error methods on the user’s positioning accuracy is verified. The results show that CNMP can effectively eliminate the influence of code noise and multipath error in the service performance evaluation of satellite-based augmentation system, and the horizontal accuracy of 95% is increased by 0.2 m, and the vertical positioning accuracy of 95% is increased by 0.47 m.