The invention discloses a nano laser based on metal tip and air slot surface plasmon polaritons. The nano laser comprises an insulating layer, and a gain medium cavity, an air gap layer and a metal tip layer which are connected by the insulating layer, wherein the air gap layer is an air slot of the insulating layer, and is arranged at the middle position of the upper edge of the insulating layer; the gain medium cavity is arranged above the air gap layer, and the cross section of the gain medium cavity is connected with the cross section of the air gas layer by two intersection points; and the metal tip layer is arranged below the air gap layer, and the metal tip layer is coated by the insulating layer, one tip of the cross section of the metal tip layer is intersected with the cross section of the air gap layer into one point. The nano laser disclosed by the invention is low in energy loss, can be implemented at the room temperature, has a smaller threshold value, can reasonably balance energy loss and local mode limitation, is convenient to manufacture, has a smaller size, and has the smaller threshold value and more excellent comprehensive performance.