Environment Protection and Food Security are included in the key issues of people’s livelihood during the Twelfth Five-Year Plan. The waste oil, which direct discharge of it would pollute the environment, thus threatening the environment; what’s more, it would do great harm to the health of people, challenges food security seriously. Enhancing the supervision of waste oil is an important task of social problem. Based on the practical researches in some areas such as Beijing and Chongqing, with other studies about the same subject and comparison of the experience abroad, this article elaborates on the current status, causes and hazards of the waste oil systematically. It also has put forward a sound system of supervision. All of these are important for people to have better understanding and complete solution of the problem.