By taking the data of Shanghai and Shenzhen A-share listed companies during 2008-2010 as the example，this paper examines the influence of earnings management degree on enterprise investment efficiency from different directions of earnings management，and the research finds that properly positive earnings management is conducive to mitigating the insufficiency of enterprise investment but excessively positive earnings management can deteriorate the shortage of enterprise investment，that negative earnings management always produces the problem in investment shortage，that properly positive earnings management can boost the confidence of the investors to ease the financing constraint of an enterprise，that the supervising departments should be able to endure the enterprises to conduct proper earnings management but should not only emphasize so-called “real accounting information”.