1. Foreigners' investment behavior have changed very much after the subprime mortgage crisis. 2. The most noteworthy behavior is the shortening of the investment duration and trade turnover rate level up. The investment scheme upgrade made the weight of foreigners' influence increased even though the foreigners' weight of holding securities decreased. 3. In order to survey the above pattern, the stock trade behavior model was set up. It was observed that the structural shift has been made after subprime mortgage crisis in the later part of 2007. Marked difference was the risk aversion behavior after 2007. 4. The phenomenon of the foreigners' investment behavior change toward the short-term investment and risk aversion will extend the possibility of disturbing factors to Korean stock market. 5. Therefore, it is recommended, as a policy, both the close monitoring foreigners' stock investment behavior and the strengthening Korean institutional investors such as government and private pension funds, etc.