Social Security′s effect on child economic support for ageing parents has been a central issue in academic research and debate.Drawing upon data from 2011 Aged Care at Home Survey in China,this paper analyzes the factors that influence child economic support for their parents,including the basic characteristics of the elderly themselves,family condition,and income of their children.Focus is placed on the impact of social security.Results show that social security for the elderly generally leads to a higher level of child economic support,this is because social security releases demands for medical and health services of the elderly,increasing the related expenditure and child economic support.There are differential impacts among sub-groups of the elderly,which are essentially differences between social strata in distribution of medical and health resources and services as a result of the various drawbacks of the current medical and health system.Policy implications for equalizing health security and improving welfare are discussed.