This paper starts with the connotation of social foundation.The authors argue that the social foundation ought to include education,social knowledge base,culture and social psychological structure,information exchange and knowledge networks,social organizing norm and incentive systems for innovation,etc.And nowadays there are a lot of work that need to be done in China in terms of constructing innovative nation,which include continually upgrading citizen' quality of science and culture,nurturing entrepreneurship,cultivating social atmosphere with practical and flexible spirit,esteeming creation,tolerating failure,probing innovation organization form suitable for modern society,perfecting innovation incentive systems.These aspects are thought as in-depth social innovation.