The invention discloses a light emitting device and an application thereof in same in detecting current intensity or voltage and displaying current direction. The light emitting device comprises a light emitting wire and a control circuit, wherein the control circuit controls the light emitting wire to emit lights; the control circuit comprises a controller, an AC (Alternating Current) control switch and an inverter; the inverter converts direct current into alternating current so as to supply power to the light emitting wire; the controller controls the AC control switch; the AC control switch controls the on-off of a corresponding light emitting wire circuit; and the light emitting wire comprises more than two light emitting wire bodies that are spirally twisted with each other. The light emitting device disclosed by the invention has the advantages of simple structure and convenience in use and can be used as an ornament after being electrified. According to the invention, when electric wires sandwiched in the light emitting wire bodies, the direction of the current can be indicated by sequentially lightening the light emitting wire bodies in circulation, and the current intensity or voltage can be indicated through a time interval of lightening the light emitting wire bodies in sequence in circulation.