The present disclosure relates to a LED lamp source and the manufacturing method and the backlight module thereof. The LED lamp source includes a substrate and a LED chip, fluorescent adhesive, and a white reflective layer being fixed on the substrate. The fluorescent adhesive encapsulates the LED chip on the substrate, and the white reflective layer is configured for reflecting light beams emitted from the fluorescent adhesive and being radiated on the white reflective layer. A positive projection of the fluorescent adhesive on the substrate is within the positive projection of the white reflective layer on the substrate.