In view of the technical pain points of the traditional three-color chip light source in the field of adjustable color gamut technology, such as the chip light decay, different temperature characteristics, discontinuous spectrum, and complex structure of the five-color light source process, a three primary color COB LED light source with high colour rendering index(CRI) and adjustable color gamut is designed and manufactured by appling fluorescent powder zonal sprayed on the surface of blue LED chip based on COB package. The test result shows that by adjusting the driving current of the chip in each region, the luminous intensity of the three-color light can be changed to realize the intelligent color matching. At 3 000~6 000 K color temperature, six groups of color coordinates under the seven color temperatures of the selected sample light source are located on the Planck curve. The lowest CRI is 72.9 and the highest is 83.4, higher than the 34.2 and 44.5 of the traditional RGB chip light source, and the spectrum continuity is better. It opens up the technological innovation of adjustable color gamut, can be better applied to the commercial lighting with high requirement of display finger.