Long - term care insurance provides an opportunity to break the dilemma under the practicalproblem of the moderately aging population and rising medical costs in China. Based on data from China Healthand Retirement Longitudinal Study(CHARLS)in 2011，2013，2015 and 2018，this paper analyzes the impactof the first batch of long-term care insurance pilot policies on the out-of-pocket medical expenses of targetgroups in pilot cities using the Difference - in - Difference method. The results showed that long - term careinsurance significantly reduced out-of-pocket medical expenses for the middle-aged and elderly population. Theabove empirical results have passed a series of robustness tests. Furthermore，the effect of long - term careinsurance on reducing out-of-pocket medical costs is more significant in urban and western areas. The empiricalresults of this paper have practical implications for extending the pilot range of long-term care insurance andrefining the treatment design.