This paper intends to investigate herding behavior of mutual fund managers participated in Taiwan stock market, especially as they were facing the regional and global financial crises in 1997 and 2008. Furthermore, it identifies fund managers’ optimal choices of trading strategies as they are facing the shallow-dish characteristics in Taiwan stock market. The empirical results reveal that fund managers do herd as they are picking up their portfolios. Instead of pursuing stocks with high speculative intensity, mutual fund managers adhere to the prudent rule to trade. However, the trading styles are not robust during the period of 1997 Asian financial crisis.