Vegetables are rich in many essential nutrients and are a major source of vitamins and minerals. However, the process of cooking vegetables often results in the loss of nutrients. To preserve the nutrients of vegetables, we should avoid the poor production process and eating habits, such as cutting first and then washing, cooking too long, too much oil, eat overnight vegetables, abandon the juice and soup, cold meals inappropriate and so on. We should pay attention to the following points: First, wash before cutting. The water-soluble vitamins and minerals in vegetables may be lost through the cuts. Secondly, the water boiled under the vegetables. B vitamins, vitamin C and other water-soluble vitamins in the heating may cause loss. Third, stir-fry quickly. Can shorten the time of heating vegetables, reduce the loss of nutrients. However, for some bean vegetables such as lentils, need to be fully heated to remove natural toxins. Fourth, fried ready to eat. Repeated heating will cause nutrient loss. And preventing too long may increase the content of nitrite.