This paper proposes a modification to Minority Game (MG) by adding some agents who play majority game into MG. So it is referred to as Mix-game. Through simulations, this paper finds out that the fluctuations of local volatilities change a lot by adding some agents who play majority game into MG, but the stylized features of MG don’t change obviously except agents with memory length 1 and 2. This paper also uses mix-game to model Shanghai stock market and to do prediction about Shanghai index.