The investment strategy of mutual funds is the focus of common concern among academia, regulators and market participants. Based on the behavioral asset pricing theory, this paper quantifies fund investment strategies as the market sentiment sensitivity of portfolio returns and it is classified as sentiment catering strategy and contrarian strategy according to market conditions for the first time at the micro-level. To explore the systematic influence of investment strategy selection on fund flow, risk and manager’s effort by theoretical models and empirical tests, and analyze the influence mechanism of fund performance from the perspective of behavioral principal-agent. The result shows that, funds are more attractive to investors, especially individual investors when adopting the sentiment catering strategy, however, it will cause hidden infringements on the interests of investors, which is manifested by increased risks and reduced returns of the fund in the future, and fund managers achieve higher returns without having to pay more efforts. Further analysis shows that the passive laissez-faire behavior of fund managers only to please investors is an important reason for their poor performance; when the fund adopts the contrarian strategy, the effects are completely opposite. This study provides new approaches and enlightenment for the investment practice of small- and medium-sized, fund governance and supervision, and the explanation of fund market anomalies.