An atomizer for an e-cigarette comprising an atomizing assembly, the atomizing assembly comprising: an atomizing head comprising an atomizing core and an atomizing tube, the atomizing tube sleeved over the atomizing core, an outer side of circumference of the atomizing core defining a least one airflow channel; and a ventilation assembly fixed to an upper end of the atomizing tube, the at least one airflow channel communicating with the ventilation assembly, wherein, air is capable of entering the atomizing core through the ventilation assembly and the airflow channel, the atomizer further comprises a liquid storage assembly, the liquid storage assembly defines a liquid storage cavity, an upper end of the atomizing assembly is sleeved over the liquid storage assembly; a lower end of the atomizing assembly is suspended in the liquid storage cavity, or abuts against a lower end surface of the liquid storage assembly; the atomizing head is located at the lower end of the atomizing assembly, the ventilation assembly is located at the upper end of the atomizing assembly, the liquid storage assembly comprises a first electrode, the atomizing assembly comprises a second electrode, the first electrode is electrically connected to the second electrode, the atomizing assembly further comprises an air adjusting device positioned at an end of the ventilation assembly opposite to the atomizing head, the air adjusting device is configured to adjust the amount of airflow entering into the atomizer, the ventilation assembly comprises an inner tube, an outer tube and a ventilation cover, an end of the outer tube is fixed to the atomizing head base, another end of the outer tube is fixed to the ventilation cover, the outer tube is sleeved over the inner tube, an end of the inner tube is fixed to the ventilation cover, another end of the inner tube is suspended in the outer tube, the air adjusting device consists of the outer tube and the ventilation cover, the ventilation cover is rotatably sleeved over the outer tube, a first ventilation portion is defined on the outer tube, a second ventilation portion is defined on the ventilation cover, the port size between the first ventilation portion and the second ventilation portion is adjustable by rotating the ventilation cover, a pin bolt is positioned on the outer tube, the pin bolt is configured to limit the rotating angle of the ventilation cover. an atomizing head comprising an atomizing core and an atomizing tube, the atomizing tube sleeved over the atomizing core, an outer side of circumference of the atomizing core defining a least one airflow channel; and a ventilation assembly fixed to an upper end of the atomizing tube, the at least one airflow channel communicating with the ventilation assembly, wherein, air is capable of entering the atomizing core through the ventilation assembly and the airflow channel, the atomizer further comprises a liquid storage assembly, the liquid storage assembly defines a liquid storage cavity, an upper end of the atomizing assembly is sleeved over the liquid storage assembly; a lower end of the atomizing assembly is suspended in the liquid storage cavity, or abuts against a lower end surface of the liquid storage assembly; the atomizing head is located at the lower end of the atomizing assembly, the ventilation assembly is located at the upper end of the atomizing assembly, the liquid storage assembly comprises a first electrode, the atomizing assembly comprises a second electrode, the first electrode is electrically connected to the second electrode, the atomizing assembly further comprises an air adjusting device positioned at an end of the ventilation assembly opposite to the atomizing head, the air adjusting device is configured to adjust the amount of airflow entering into the atomizer, the ventilation assembly comprises an inner tube, an outer tube and a ventilation cover, an end of the outer tube is fixed to the atomizing head base, another end of the outer tube is fixed to the ventilation cover, the outer tube is sleeved over the inner tube, an end of the inner tube is fixed to the ventilation cover, another end of the inner tube is suspended in the outer tube, the air adjusting device consists of the outer tube and the ventilation cover, the ventilation cover is rotatably sleeved over the outer tube, a first ventilation portion is defined on the outer tube, a second ventilation portion is defined on the ventilation cover, the port size between the first ventilation portion and the second ventilation portion is adjustable by rotating the ventilation cover, a pin bolt is positioned on the outer tube, the pin bolt is configured to limit the rotating angle of the ventilation cover.