Based on 663 A-share market high-tech enterprises from 2004-2011,this paper makes an empirical study of the relationship between the share holdings of securities investment fund which is a typical type of institutional investors and R&D investment. The results show that securities investment funds do not have a significant positive correlation with R&D investment when we regard securities investment funds as homogeneous institutional investors; we also find that long-term investors have a significant positive correlation with R&D investment while short-term opportunists have a significant negative correlation with R&D investment when we regard securities investment funds as heterogeneous institutional investors and divide it into long-term investors and short-term opportunists.