Disclosed are a backlight source and a manufacturing method thereof, wherein the method of manufacturing the backlight source comprises the following steps: forming a base layer, a dielectric layer, and a conductive layer stacked successively from bottom to top to form a semi-finished PCB; the semi-finished PCB is divided into a light bar area and a heat dissipating area; the conductive layer is divided into a first conductive area and a second conductive area insulated from each other; etching the second conductive area to form a preset conductive circuit; spraying insulating paint upon the conductive layer to form the insulating layer, thus producing the PCB; and installing the LED onto the light bar area and making it in electrical connection with the second conductive area.