A cartridge (100) of an electronic cigarette includes an oil reserving pipe (2), an oil obstructing plug (3) and a heating assembly (4). The oil reserving pipe has an inner space (21) for reserving a tobacco oil. The oil obstructing plug is arranged at an end of the oil reserving pipe and has an oil hole (31) in communication with the inner space. The heating assembly is arranged under the oil obstructing plug and configured for heating and atomizing the tobacco oil penetrating through the oil hole. An atomizing device using the cartridge, and an electronic device using the atomizing device are also provided.