An atomisation assembly, an electronic cigarette, and a method for preventing a child from smoking an electronic cigarette by accident. The atomisation assembly comprises an atomisation assembly body (3), and a mouthpiece assembly (1) movably connected to one end of the atomisation assembly body (3). A valve mechanism (2) controlling the connection and disconnection of vapour channels (11, 34) via rotation is arranged between the atomisation assembly body (3) and the mouthpiece assembly (1), the valve mechanism (2) comprising a first extension pipe (311) formed by extending from an end surface of the atomisation assembly body (3) in the direction away from a liquid storage chamber (33), and a second extension pipe (211) formed by extending from an inner wall of the mouthpiece assembly (1) in the direction of the liquid storage chamber (33), and connected in a docking manner with the first extension pipe (311). The first extension pipe (311) and the second extension pipe (211) are accommodated within an e-liquid condensation chamber (4). The arrangement of the valve mechanism (2) within the vapour channels (11, 34) of an electronic cigarette, the valve mechanism (2) being capable of closing or opening the vapour channels (11, 34) via rotation of the mouthpiece assembly (1), prevents the electronic cigarette from operating automatically during transportation, and also prevents a child from smoking the electronic cigarette by accident.