Abstract: The performance of the Klobuchar model of both Beidou satellite navigation system(BDS) ionosphere and Global Position System(GPS) ionosphere are simulated and analyzed based on the RINEX data to choose a more optimal ionosphere model for BDS/GPS integrated navigation. And by using two weighted RAIM algorithms which are satellite constellation type based and satellite type based, different RAIM availabilities are analyzed in the Non-Precision Approach (NPA) phase and Approach Vertical Guidance Ⅰ(APVⅠ) phase of the flight process respectively for the signal BDS navigation, the signal GPS navigation and the BDS/GPS integrated navigation based on the better ionosphere model. The experimental results show that more ionosphere delay can be corrected by applying the Klobuchar model of BDS compared with the Klobuchar model of GPS. The ionosphere delay correction of the BDS model has an improvement of 0 to 3.4364m compared with that of GPS model. For both two weighted RAIM algorithms during the NPA phase, the RAIM availability of the integrated navigation is 100%, and the RAIM availability of either the signal BDS navigation or the signal GPS navigation is approximately 90%. However，for both two weighted RAIM algorithms during the APVⅠphase, the two single constellation navigation methods can not satisfy the APVⅠability, but the RAIM availability of the BDS/GPS integrated navigation reaches 100%, and have the ability to provide the APVⅠapplication.