中文摘要：

本文利用状态空间模型估计出我国城镇居民所有收入阶层边际消费倾向（MPC）的波动趋势。实证检验结果表明：所有收入阶层的MPC于1988年突然上升以后回落，而最低收入阶层从1990年开始其MPC持续上升，并于2004后开始下降；而其他6个收入阶层的MPC从1988开始持续快速下降，于1994年后下降趋势变缓，但2004年后也快速下降；不同收入阶层的MPC逐步呈现发散的趋势，同时，MPC随着收入水平的增加而递减。本文从多个角度对实证结果进行了解释，最后提出了相应的政策建议。

英文摘要：

By a state-space model, this paper measures the volatility ot urban inhabitants＇ propensity to consume （MPC） in China from the angle of different income classes. The empirical results are shown as follows： first, general MPC suddenly rose in 1988 and slowed down then, but MPC of the lowest income class had been constantly increasing since 1994 and started decreasing after 2004; secondly, MPC of other 6 incomes classes has been constantly and quickly reducing since 1988 and the downtrend had been slower from 1994 to 2004; thirdly, MPC of different income classes is featured by a scattering tendency step by step, and MPC decreases as the income level rises. This paper gives an explanation of empir ical results and provides corresponding policy suggestion.