From 2018 to 2019, the BDS-3(BeiDou navigation satellite system phase Ⅲ) has successively launched more than a dozen MEO(medium earth orbit) satellites, gradually completing global networking. The BDS-3 satellites simultaneously broadcast smooth transition signals B1I, B3I and new signals B1C, B2a.The analysis of actual data shows that the civil B1C frequency and B1I frequency of MEO satellites contains obvious pseudorange multipath errors. Due to the orbital characteristics of MEO satellites, this phenomenon is very significant at low altitude angles of satellites. Two algorithms of MHM(multipath hemispherical map) and CNMC(code noise and multipath correction ) were used to correct the pseudorange multipath error. The correction of the pseudorange multipath error by the MHM algorithm was not obvious. The CNMC algorithm can reduce the B1C frequency multipath error from 0.11 m to 0.03 m and reduce the B1I frequency multipath error from 0.074 m to 0.024 m when the altitude angle is greater than 30 degrees. The multipath error of the MEO satellite is reduced by about 60%.