Abstract: The BeiDou satellite-based augmentation system (BDSBAS) realizes simultaneous augmentation of multiple satellite constellations by broadcasting dual-frequency augmentation messages through B2a signal to provide users with more accurate and reliable positioning and navigation services. In order to meet the demand of civil aviation for the positioning performance of BDSBAS in the approach phase, this paper researches the BeiDou satellite-based augmentation dual-frequency positioning algorithm, and evaluates the performance of the dual-frequency service of BDSBAS based on the data of the static station and the flight data in terms of the accuracy and integrity. The static experiment data were collected from the BDSBAS site in Beijing on January 17, 2024, for the whole day. The flight measurement data were collected from the aviation test conducted at Faku Caihu General Aviation Airport in Shenyang. The static evaluation results show that the positioning errors of Beijing, Xi’an and Jiayuguan stations were relatively stable during the evaluation period. The horizontal positioning accuracy (95%) was better than 2 m; the vertical positioning accuracy (95%) was better than 3 m. Horizontal availability was better than 99.998% and vertical availability was better than 99.984%. The results of the flight test show that the horizontal and vertical accuracy during the test were 1.8269 m and 2.6014 m, respectively, and no integrity event occurred. The static and dynamic evaluation results met the requirements of the International Civil Aviation Organization (ICAO) APV-I indexes for accuracy and integrity. The results of this study are meaningful for the performance evaluation of BDSBAS.