Through investigating the Smart Grid System Report submitted by US Department of Energy（DOE） to the Congress， as well as Financial Opportunity Announcement of DOE related with smart grids and investments in recent years， this paper studies on the emphasis and short term target of smart grid development in the US， especially the status and development of distributed generation in smart grids in the US. Based on the classification and statistic indices， the investigation on the development trend and investment ration of smart grids shows that the focus of smart grid development in the US is on the distribution system side.