A helical antenna, including a printed circuit board and a radiating body provided above the printed circuit board. The radiating body includes at least one main helical arm and at least one parasitic helical arm. Each main helical arm corresponds to at least one parasitic helical arm. Each main helical arm is arranged in parallel with and is spaced with its corresponding parasitic helical arm. A first terminal of each main helical arm is electrically connected to a first terminal of the corresponding parasitic helical arm. A second terminal of the main helical arm and a second terminal of the parasitic helical arm are both in a floating state, and a length of the parasitic helical arm is greater than a length of its corresponding main helical arm.