中文摘要：

缩小收入差距能否提高居民总消费取决于边际消费倾向的特征，而边际消费倾向的特征受多种因素影响。本文通过建立离散模型，证明“当且仅当”边际消费倾向递减时，缩小收入差距才能提高总消费，进而基于对数效用函数假设推导出边际消费倾向函数。结果表明：边际消费倾向函数是复杂的非线性函数，价格、利率、对外开放程度等变量是影响边际消费倾向的重要因素，但边际消费倾向是否递减则取决于参数条件的检验。基于2000—2009年省际面板数据的参数检验结果表明，我国城镇居民边际消费倾向递减，从而缩小收入差距可以提高总消费，进一步的实证分析也表明，基尼系数对我国城镇居民平均消费倾向的影响系数达-0．823。本文的方法和结论相对以往研究有一定的改进。

英文摘要：

Whether narrowing income gap can increase aggregate consumption depends on the feature of marginal propensity to consume （MPC） which is influenced by multiple factors. By constructing a discrete model,we proved that if and only if the MPC of an individual falls as his disposable income rises; narrowing income gap can result in a increase in consumption. The MPC function based on the assumption of Logarithmic utility function shows that： price,interest rate and openness are the important factors to influence the MPC, and whether the MPC decreases depends on empirical test of the parameters. The result of empirical test by using the data of urban residents of China （2000 -2009） shows that the MPC of Chinese urban residents fall as their income rises. Therefore, equalizing the income distribution will give rise to the increase of aggregate consumption. The following empirical research also shows that the influence coefficient of Gini coefficient to average propensity to consume is - 0. 823. The method and results have been improved in this study compared to previous research.