The invention provides a flip LED chip and a forming method thereof. The forming method comprises the following steps: providing a substrate; forming an N-type semiconductor layer, an active layer and a P-type semiconductor layer; forming an opening that a part of the N-type semiconductor layer is exposed out; forming a P electrode layer, an N electrode layer and an insulated reflecting layer; and forming a P electrode structure and an N electrode structure. The flip LED chip comprises the substrate, the N-type semiconductor layer, the active layer and the P-type semiconductor layer, wherein the P electrode layer is arranged on the P-type semiconductor layer, and the N electrode layer is arranged on the N-type semiconductor layer in the opening; the P-type semiconductor layer, the P electrode layer, the N-type semiconductor layer and the N electrode layer are covered with the insulated reflecting layer; and the P electrode structure electrically connected with the P electrode layer and the N electrode structure electrically connected with the N electrode layer are formed in the insulated reflecting layer. Theflip LED chip has the beneficial effects that partial light rays can be reflected to the substrate while the insulated reflecting layer plays an insulated isolation role, so that the increase of light transmittance of the flip LED chip is facilitated.