Abstract: This invention discloses a method for HID lamp to be lighted instantly when power is on and the related HID lamp. The method is to connect two luminous bodies in parallel and then link it with the power supply through a ballast. When the power is turned on, only one HID luminous body is lighted up; when power is turned off and turned on again, the other HID luminous body is triggered to light up. The HID lamp that can light instantly when power on includes a lamp cap, lamp shape and a ballast that connects the power supply and the lamp cap. There are at least two HID luminous bodies, each of which is connected in parallel. Two lead wires are connected with the lamp cap respectively. In this invention, at least two HID luminous bodies are connected in parallel. When HID light is turned on, only one HID luminous body is lighted up. When it is turned on again, other HID luminous bodies that are connected in parallel are triggered to light up.