An LED light source comprises a lower substrate having an upper surface which is formed with a groove and covered with an insulating layer in an area outside the groove, wherein the insulating layer is partially covered with a metal layer; an upper substrate disposed on a top of the insulating layer and formed with an opening in an area corresponding to the groove; a plurality of sub-substrates disposed on an inner bottom portion of the groove, wherein each said sub-substrate has a surface covered with a circuit layer, adjacent said sub-substrates are electrically connected to each other at respective adjacent ends thereof by a first metal lead, and each said sub-substrate is provided thereon with a plurality of LED chips, in which each said LED chip is connected by a second metal lead to a corresponding electrical connection point; and a light-transmitting colloid filled in the groove and the opening. The plurality of LED chips are thus integrally packaged in the groove to form the LED light source, which can be easily manufactured while having a small volume and providing high brightness.