Since the BDS-3 started providing positioning, navigation and timing services to global users, to evaluate the effect of the different orbiting satellites of BDS-2 on the SPP performance of BDS-3, we combined the GEO, IGSO and MEO satellites of the BDS-2 constellation with the satellites of the BDS-3 in terms of the number of visible satellites, PDOP and SPP accuracy. The results show that the SPP performance of the BDS-2 IGSO satellites combined with BDS-3 was the best, the BDS-2 GEO combined with BDS-3 was the second and BDS-2 MEO combined with BDS-3 was the third. The horizontal and vertical accuracy of the BDS-2 GEO, IGSO and MEO satellites combined with BDS-3 respectively indicated that the combination of BDS-2 IGSO and BDS-3 mainly improved the horizontal accuracy, the combination of BDS-2 GEO and BDS-3 primarily improved the vertical accuracy, and the combination of BDS-2 MEO with BDS-3 improved both the horizontal and vertical accuracy.