The present invention relates to a mouthpiece device of an electronic cigarette, including an atomizing device for vaporizing tobacco liquid into aerosol and a liquid reservoir for storing tobacco liquid in an inhaling shell. The atomizing device includes an atomizing cup with an atomizing chamber, and an atomizer held in the atomizing chamber. The atomizing cup is molded by an integrated process. The mouthpiece device further includes a cap at an end of the liquid reservoir, and an aerosol passage therein: The cap defines a stepped slot for filtering tobacco particles in aerosol. The stepped slot is communicated with the aerosol passage. The present invention mainly solves such problems of the existing mouthpiece device as complicated manufacturing, high cost, bad heat insulation, and failing to filter tobacco particles and obtains a mouthpiece device with simple manufacturing, lower cost, good heat insulation and better effectiveness of filtering tobacco particles.
