Presently, a white light LED is formed by irradiating yellow fluorescent substances by a blue light. Particularly, a blue light GaN LED is sealed with a phosphor layer to form the white light LED. The sealing process comprises the following steps. A chip of the blue light GaN LED is fixed on a support of a cup structure, and then a mixture of a fluorescent substance and an adhesive is filled in the support of the cup structure with a spin coater, thus forming a phosphor layer. In this way, the phosphor layer may not have a flat surface, thus causing problems like light spots and light inconsistency. With higher and higher requirements on light consistency and color rendition in the application of LED TVs and LED headlights of automobiles, the sealing problems may need to be solved.