An elastic locking mechanism, an atomizer for an electronic cigarette, and an electronic cigarette are disclosed. The elastic locking mechanism includes an upper cover removably arranged on an opening end of a liquid storage assembly, a screw cap sleeved outside the upper cover, an upper engagement component arranged on the screw cap, a lower engagement component arranged on the upper cover, and an elastic element mounted between the screw cap and the upper cover to prevent the upper engagement component and the lower engagement component from engaging each other. When the screw cap is pressed down or pulled up, the elastic element is compressed or stretched so that the upper engagement component engages the lower engagement component, and the upper cover is driven to rotate together with the screw cap by rotating the screw cap.