LED lighting has the advantages of small volume, energy saving, environmental protection, high luminous efficiency, fast response, vibration resistance and long service life. It will become a new type of lighting source in the 21st century. The reliability of LED lighting source refers to that the LED can meet the functional requirements of photoelectric and appearance within the specified service life. Product reliability determines the key quality of the product and the LED brand effect. Among them, LED white light products use the most, and some are used in one product (such as retail store display, decorative lighting, etc.), which requires better color consistency. The inconsistency of LED color is what we call "color difference", which leads to uneven color of backlight products, dissatisfaction of customers and unsalable products. Therefore, the color difference of white light products is another key factor restricting the quality of products.