The solderability of three kinds of high viscosity(180Pa. s) pastes(Sn-3. OAg-0. 5 Cu，Sn-58 Bi andSn一17. OBi-0. SCu)were studied by the high-frequency induction heating equipment and the area on brass substrate. The Passive Intermodulation(PIM)was compared by the PIM testing and the porosity of brass oscillator af-ter SAC305 and SBC1705 solder pastes soldering was compared by the X-ray detection. The results showed that thesolderabnty of high mscosity paste SBC1705 is the best on brass substrate，followed by Sn-58 Bi solder paste，andfinally SAC305 solder paste;the porosity of SBC1705 solder joints is less than 1%，while the porosity of SAC305solder joints is 5 % to 7 %，the porosity of the two solder joints are within the acceptable range25%)，but thePIM test results of oscillator after SBC1705 soldering are more stable. Comprehensive considerations，high viscositysolder paste SBC1705 is more suitable for radio frequency antenna brass oscillator induction soldering process.