The present invention discloses a light emitting diode structure and a method for fabricating the same. In the present invention, a substrate is placed in a solution to form a chemical reaction layer. Next, the substrate is etched to form a plurality of concave zones and a plurality of convex zones with the chemical reaction layer overhead. Next, the chemical reaction layer is removed to form an irregular geometry of the concave zones and convex zones on the surface of the substrate. Then, a semiconductor light emitting structure is epitaxially formed on the surface of the substrate. Thereby, the present invention can achieve a light emitting diode structure having improved internal and external quantum efficiencies.