This paper finds that fund managers’confidence is a new factor, in addition to the traditional optimistic (pessimistic) tone, that affects the performance of Chinese mutual funds. This paper uses the annual and semiannual reports of mutual funds in China from 2010 to 2020 to construct fund managers’confidence indicators. The empirical results show that the managers’ confidence indicator has a positive predictive ability for mutual fund’s future performance. After being adjusted by the Chinese threefactor model, the arbitrage portfolio significantly earns an annualized excess return of more than 2.4〖WTXT〗%〖WTBZ〗. Further, fund managers’confidence contains incremental information beyond the traditional optimistic (pessimistic) tone. On average, arbitrage portfolios earn an annualized excess return of more than 2〖WTXT〗%〖WTBZ〗 when controlling for indicators of the manager’s optimistic (pessimistic) tone. Finally, managers’confidence and “overconfidence” also distinguished. Confident fund managers are more committed to their investment philosophy and reduce the frequency of future trades. Fund managers benefit from the fact that fund turnover decreases as confidence increases.