中文摘要：

恩格尔系数作为衡量居民生活水平的重要指标,其理论基础是恩格尔定律。作为实证性定律,恩格尔定律并没有严格的理论推理,其在我国的应用也受到一些质疑。本文基于效用函数假设和马斯洛层次需求理论,对恩格尔定律进行了理论推导;并利用省际面板数据（1981～2010）对模型进行了检验,结果表明恩格尔定律在我国是成立的。因此,使用恩格尔系数评价和比较我国居民生活水平是可靠的。

英文摘要：

The Engel coefficient is an important indicator to measure people＇s living standards, and it＇s theoretical basis is Engel＇s law. As the empirical law, the Engel＇s Law has not been reasoned theoretically and its application in China has also been questioned a lot. Based on assumptions of utility function and the Maslow＇s Hierarchy of ＂Needs＂ Theory, we conduct the Engel＇s Law theoretically. Then we use the inter-provincial panel data （1981-2010） to validate the model, and the results show that Engel＇s law in our country is established. Engel coefficient is reliable to evaluate and compare the living standards.