An atomizer, comprising: a housing assembly defining a liquid chamber configured for storing tobacco liquid; an atomizing core arranged in the housing assembly, the atomizing core being configured for atomizing the tobacco liquid; a lid being connected with the housing assembly, the lid being configured for sealing the liquid chamber, the lid being detachable from the housing assembly so that tobacco liquid can be filled into the liquid chamber; a liquid blocking cover movably arranged in the housing assembly, the liquid blocking cover being detachably connected with the lid; and an elastic element elastically abutting against the liquid blocking cover; when the lid is connected with the liquid blocking cover, the lid is capable of driving the liquid blocking cover to move to a first position where the tobacco liquid in the liquid chamber can flow to the atomizing core; when the lid is detached from the housing assembly, the liquid blocking cover is driven by the elastic element to a second position where the atomizing core is isolated from the liquid chamber, wherein the lid is rotatably connected with the housing assembly, and the lid and the liquid blocking cover are threadedly coupled with each other; the atomizer further comprises a mouthpiece arranged on the lid, and an air pipe between the mouthpiece and the atomizing core, wherein the liquid blocking cover nest the air pipe, and is slidable along an axial direction of the air pipe; characterized in that the air pipe comprises an obstructing part, and the obstructing part is configured for preventing the liquid blocking cover from rotating when the lid is threadedly connected with the liquid blocking cover. a housing assembly defining a liquid chamber configured for storing tobacco liquid; an atomizing core arranged in the housing assembly, the atomizing core being configured for atomizing the tobacco liquid; a lid being connected with the housing assembly, the lid being configured for sealing the liquid chamber, the lid being detachable from the housing assembly so that tobacco liquid can be filled into the liquid chamber; a liquid blocking cover movably arranged in the housing assembly, the liquid blocking cover being detachably connected with the lid; and an elastic element elastically abutting against the liquid blocking cover; when the lid is connected with the liquid blocking cover, the lid is capable of driving the liquid blocking cover to move to a first position where the tobacco liquid in the liquid chamber can flow to the atomizing core; when the lid is detached from the housing assembly, the liquid blocking cover is driven by the elastic element to a second position where the atomizing core is isolated from the liquid chamber, wherein the lid is rotatably connected with the housing assembly, and the lid and the liquid blocking cover are threadedly coupled with each other; the atomizer further comprises a mouthpiece arranged on the lid, and an air pipe between the mouthpiece and the atomizing core, wherein the liquid blocking cover nest the air pipe, and is slidable along an axial direction of the air pipe; characterized in that the air pipe comprises an obstructing part, and the obstructing part is configured for preventing the liquid blocking cover from rotating when the lid is threadedly connected with the liquid blocking cover.