Air filter integrated with internally-inserted pipe

The invention discloses an air filter integrated with an internally-inserted pipe. The air filter comprises an air inlet side expansion cavity which is communicated with an air inlet pipe, a filter core, and an air outlet side cavity which is communicated with an air outlet pipe, wherein the air outlet pipe is communicated with the air outlet side cavity through the internally-inserted pipe; the air inlet end of the internally-inserted pipe is positioned in the air outlet side cavity; the air inlet end of the internally-inserted pipe is flared, and is over against the filter core of the air filter; the air outlet end of the internally-inserted pipe is connected with the air inlet end of the air outlet pipe. By adopting the air filter, the noise can be reduced, and the resistance loss of air current can be reduced.