The invention provides a low passive intermodulation feed source duplexer, and a receiving and emitting method thereof. A duplexer cavity body and an antenna feed source base are designed and processed in an integral manner in terms of structures, the sizes of the duplexer and the antenna feed source can be accurately calculated. A shared resonance rod of the duplexer and inner and outer conductors at a feed source input interface can be co-designed in that a matching port impedance can be designed, the shape, size and distance of the shared resonance rod can be adjusted, and the phase position between two devices can be optimized. Accordingly, an integral design can be realized. The invention is advantageous in that the situation of the conventional design that the duplexer is connected to the antenna feed source through cables can be prevented, and the usage of electric connectors can be reduced, and the part depending on elastic connection can be removed; the contact nonlinearity ofsensitive parts can be prevented, and the PIM feature of the product can be greatly improved, and the aim of reducing the PIM of the system can be achieved; the problem of passive intermodulation inhibition of the microwave duplexer and the antenna feed source system can be resolved.