An atomizer, electronic cigarette and method for assembling the atomizer, wherein the atomizer is configured to be connected to a battery sleeve to form an electronic cigarette, comprising an oil storage cavity, a holding cavity, a heating assembly received in the holding cavity, and an electrode assembly configured to be electrically connected to the battery rod; the heating assembly including a heating wire electrically connected to the electrode assembly and an oil guide rope for transferring tobacco tar to the heating wire; one side of the oil storage cavity defines an oil outlet, a clamp seat configured to clamp the oil guide rope is received in the holding cavity and is located between the heating wire and the oil outlet, and the oil guide rope extends to one side of the clamp seat away from the heating wire.