The present invention relates to the technical field of illuminating lamp, especially to an LED module and its manufacturing process. The LED module of the present invention includes a lens group, an LED illuminant, a circuit board and a heat sink; the LED illuminant includes an LED chip and a heat sink holder; the LED chip is attached to the heat sink holder which is disposed on the circuit board by Surface Mounted Technology; the lens group covers the heat sink, and is located above the LED chip; encapsulant is filled in a confined space formed between the lens group and the heat sink through a process of injection. Compared with the prior art, in the LED module of the present invention, the encapsulant replaces the original air medium in the transmission process of the light emitted by the LED chip; moreover, the matching between the refractive index of the encapsulant and the lens of the lens group improves the light out-coupling efficiency to greatest extent. Lighting efficiency is improved by 10˜15% compared with the prior art.