The present disclosure provides an LED assembly, a light source, and a liquid crystal display device. The LED assembly includes: a substrate; a plurality of blue LED chips which are disposed on the substrate at intervals and have different emission wavelengths; a white light phosphor layer which is disposed on the substrate and covers the plurality of blue LED chips; and a sealing frame which is disposed on the substrate and is configured to encapsulate the plurality of blue LED chips and the white light phosphor layer. The LED assembly encapsulates the blue LED chips having different emission wavelengths together, which can avoid LED mixing from an LED encapsulation source, thereby saving cost. Moreover, problems such as nonuniform images and chromatic aberration are basically avoided when the LED assembly is applied to an LCD module.