Silencing device for indoor ventilation fan

The utility model relates to the technical field of silencing devices, and discloses a silencing device for an indoor ventilation fan, which comprises a main body assembly, an adjusting assembly is arranged in the shell; the rotary knob is arranged at the bottom of the shell, the inner side wall of the shell is rotationally connected with the pipe body, the bottom end of the pipe body is fixedly connected with the rotary knob, and the wind shield is arranged on the outer side wall of the pipe body; noise generated when the fan works and indoor air are exhausted through the exhaust outlet, the air speed is controlled through the second air blocking piece and the first air blocking piece, the noise generated by the fan is transmitted back through the air blocking plate and matched with the partition plate to achieve the noise reduction effect, and the noise can be reduced by rotating the rotary knob and adjusting the gap between the second air blocking piece and the first air blocking piece. The air speed is ch