Natural food pigments are generally less stable and more sensitive to light, heat and enzyme bacteria. In order to maintain its natural properties and stability, the preparation method of natural food coloring is generally physical method. According to the different raw materials, uses and dosage forms of pigments, the extraction methods of natural plant pigments can be divided into 1. Extraction method, 2. Enzymatic reaction method, 3. Press method, 4. Boil method; Several new extraction methods: 1. Ultrasonic extraction method, 2. Microwave extraction method, 3. Supercritical fluid extraction, 4. Multistage or continuous extraction, 5. High pressure extraction,6. Enzyme-assisted extraction technology.