Disclosed are a novel low-pass filtering path and a communication cavity device using the same. The novel low-pass filtering path comprises a metal cavity and a cover plate for covering the metal cavity. A plurality of sub-cavities which are sequentially communicated with one another is arranged inside the metal cavity. A connecting window is provided between every two adjacent sub-cavities. A conductor rod is provided in the metal cavity and sequentially penetrates the sub-cavities which are communicated with one another. Resonance rods are provided on the conductor rod corresponding to the connecting windows, wherein the resonance rods penetrate the conductor rod, and rod bodies of the resonance rods protrude towards the cover plate. Threaded holes corresponding to the resonance rods are provided on the cover plate. A group of tuning screw rods in which mounting holes are formed penetrate the threaded holes and extend into the cavity to be in capacitive coupling with the corresponding resonance rods. Medium
