A light emitting diode (LED) array includes a substrate with an array having a plurality of LED chips thereon, a dielectric layer, a plug, and a conductive connection layer. Each of the LED chips is isolated from another LED chip adjacent thereto by a trench. The dielectric layer covers a surface of the substrate exposed by the trench and sidewalls and partial surfaces of the LED chips adjacent to the trench. The plug fills the trench. The conductive connection layer is disposed over the plug and the dielectric layer to connect the LED chips with the LED chips adjacent thereto. Radiation emitted from one of the LED chips can be reflected by the dielectric layer and the plug, and finally reflected and output from a side of the LED chip not adjacent to the trench, thereby not affecting the adjacent LED chip and being absorbed by it.