A thorough study on large-scale wind turbine is presented，and the force and torque(flap wise and edge wise) are derived from wind inflow velocity based on BEM theory. Through the Coleman transformation, a system state space equation is established. Based on the equation，the theory research on individual pitch control is studied and programmed in MATLAB/SIMULINK. The theory research and engineering application show the superiority of individual pitch control design on load reduction，which is more suitable for the control of large-scale wind turbine. Individual pitch control can reduce the load that is happened in the operation process，so as to extend system service life and decrease maintenance.