The invention discloses a light-emitting diode chip and a manufacturing method thereof, and belongs to the technical field of semiconductors. The light-emitting diode chip comprises a substrate, an n-type III-group nitride semiconductor layer, a active layer, a p-type III-group nitride semiconductor layer, a current spreading layer, an insulation passivation layer and a light extraction enhancement layer, the n-type III-group nitride semiconductor layer, the active layer, the p-type III-group nitride semiconductor layer, the current spreading layer and the insulation passivation layer are sequentially stacked on the substrate, a groove is formed in the p-type III-group nitride semiconductor layer and extends to the n-type III-group nitride semiconductor layer, a first electrode is arranged on the n-type III-group nitride semiconductor layer, a second electrode is arranged on the current spreading layer, the light extraction enhancement layer is arranged between the substrate and the n-type III-group nitride semiconductor layer and comprises a plurality of curved surface structures which are distributed in an array manner, the curved surface structures and the substrate integrally form a hollow structure, and the substrate, the curved surface structures and matters in the hollow structure are transparent. External quantum efficiency of the LED (light-emitting diode) chip is improved.