The invention discloses a Ku / Ka dual-band transmitting-receiving community antenna feed source assembly, which comprises a Ku / Ka waveband antenna feed assembly and a polarization adjusting mechanism, wherein the Ku / Ka waveband antenna feed assembly comprises a Ku waveband transmitting and receiving assembly and a Ka waveband transmitting and receiving assembly; and the polarization adjusting mechanism comprises a driving motor assembly, a transmission gear, a Ka rotation joint, a Ku transmission rotation joint and a Ku receiving rotation joint, and the driving motor assembly drives the Ka rotation joint, the Ku transmission rotation joint and the Ku receiving rotation joint to adjust a polarization angle through transmission of the transmission gear. The Ku / Ka dual modes share one feed source horn, a dielectric rod is cancelled, a full-waveguide mode is adopted, the structure is compact, the utilization rate is high, Ka circular polarization switching is facilitated, good Ku / Ka wave frequency band isolation is provided, and good polarization separation, polarization isolation, radiation features, a standing-wave ratio and gains are realized in the frequency band; and Ku line polarization adjustment can be carried out in real time, and automatic satellite aiming is realized.