The invention relates to a communication signal filter, which comprises a cover plate, a tuning rod, an energizing medium, a cavity, a resonant column, a shell, an output terminal and an input terminal. The outer side of the cavity is provided with a shell, and the shell is connected with the cavity through a clamping mode; The left outer wall of the shell is provided with an input end, and one end of the input end is connected with the shell through a mosaic mode; The right outer wall of the shell is provided with an output end, and the output end is connected with the shell through a mosaicmode; The cavity is provided with a resonant column, and the resonant column is connected with the cavity through a mosaic mode; The outer side of the resonant column is provided with an energizing medium, and the energizing medium is connected with the resonant column through a sleeve mode; The invention has the advantages of reducing the loss, thoroughly filtering and simple structure through the improvement of a communication signal filter, thereby effectively solving the problems and shortcomings proposed in the background of the invention.