An atomizer, comprising: a liquid supply configured for storing tobacco liquid; a mouthpiece at a first end of the liquid supply; an air pipe; an atomizing device at an opposite second end, the atomizing device comprising: a main body having an atomizing chamber, the air pipe connecting the atomizing chamber and the mouthpiece; a liquid conducting element in the atomizing chamber; and a heating element in contact with the liquid conducting element; wherein the liquid supply defines at least one air inlet at the first end, the air pipe and the liquid supply cooperatively define an annular air passage, the air passage is in communication with the air inlet, the main body defines at least one liquid inlet and at least one air hole, the air passage is in communication with the atomizing chamber via the at least one air hole, the liquid supply has a housing, the housing defines liquid outlets matching with the at least one liquid inlet, the liquid outlets communicates with the at least one liquid inlet, and the liquid conducting element is configured for absorbing the tobacco liquid flowed through the liquid outlets and the at least one liquid inlet from the liquid supply; characterized in that the main body comprises at least one protrusion, the at least one protrusion protrudes into the air passage, the at least one protrusion is coupled with the housing of the liquid supply by interference fit, and the at least one liquid inlet is defined in a corresponding protrusion. a liquid supply configured for storing tobacco liquid; a mouthpiece at a first end of the liquid supply; an air pipe; an atomizing device at an opposite second end, the atomizing device comprising: a main body having an atomizing chamber, the air pipe connecting the atomizing chamber and the mouthpiece; a liquid conducting element in the atomizing chamber; and a heating element in contact with the liquid conducting element; wherein the liquid supply defines at least one air inlet at the first end, the air pipe and the liquid supply cooperatively define an annular air passage, the air passage is in communication with the air inlet, the main body defines at least one liquid inlet and at least one air hole, the air passage is in communication with the atomizing chamber via the at least one air hole, the liquid supply has a housing, the housing defines liquid outlets matching with the at least one liquid inlet, the liquid outlets communicates with the at least one liquid inlet, and the liquid conducting element is configured for absorbing the tobacco liquid flowed through the liquid outlets and the at least one liquid inlet from the liquid supply; characterized in that the main body comprises at least one protrusion, the at least one protrusion protrudes into the air passage, the at least one protrusion is coupled with the housing of the liquid supply by interference fit, and the at least one liquid inlet is defined in a corresponding protrusion. a main body having an atomizing chamber, the air pipe connecting the atomizing chamber and the mouthpiece; a liquid conducting element in the atomizing chamber; and a heating element in contact with the liquid conducting element; wherein the liquid supply defines at least one air inlet at the first end, the air pipe and the liquid supply cooperatively define an annular air passage, the air passage is in communication with the air inlet, the main body defines at least one liquid inlet and at least one air hole, the air passage is in communication with the atomizing chamber via the at least one air hole, the liquid supply has a housing, the housing defines liquid outlets matching with the at least one liquid inlet, the liquid outlets communicates with the at least one liquid inlet, and the liquid conducting element is configured for absorbing the tobacco liquid flowed through the liquid outlets and the at least one liquid inlet from the liquid supply; characterized in that the main body comprises at least one protrusion, the at least one protrusion protrudes into the air passage, the at least one protrusion is coupled with the housing of the liquid supply by interference fit, and the at least one liquid inlet is defined in a corresponding protrusion.