中文摘要：

社会保障是国家调节收入差距的重要的手段之一,对缩小收入分配差距具有显著作用。采用基尼系数的改良指标G来衡量城乡收入差距,对1994—2010年的时间序列数据进行实证分析,可以得出创新性结论：农村居民社会保障水平对城乡收入差距具有周期性的影响,并由此推算出农村社会保障政策的实施时滞期大约为1.5年;农村居民社会保障支出取决于上期城镇居民社会保障支出,反映了我国当前社会保障制度二元性、优先城镇居民的特点。

英文摘要：

This paper is from the perception of the dual economy to study the relationship between social security expenditure and the urban-rural income gap.The paper uses the time series data from 1994 to 2010 and the improved index G to measure the urban-rural income gap.Through the stationary test,co-integration test,VAR model as well as the Grainger causality test,we finally draw three breakthrough conclusions that the level of rural social security expenditure has a cycle influence on the urban-rural income gap,as a result,we deduce the time-lag of the rural social security polices is about 1.5 years;The level of rural social security expenditure and the urban-rural income gap are positively correlated,but there is no cumulative effect;there exists one-way Grainger causal relationship between urban and rural social security expenditure.