In order to alleviate the unbalanced load that occurred in operation above rated wind speed in large wind turbines, for variable speed variable pitch wind turbine, this paper gives IPC (independent pitch control) strategy based on PID controller which parameters can be optimized by ACA (Ant Colony Algorithm). It uses the optimization of ACA to optimize the parameters of traditional PID pitch controller, thus to makes it has adaptiveness of PID control and streamlining of ACA, and gives its specific implementation steps. The wind turbine IPC model is constructed and the simulation and experiment of the new strategy and the traditional strategy are made. The simulation and experimental results show that the IPC based on ACA-PID is effective and practical, it can enhance the dynamic performance of the control system, effectively reduce load imbalance and improve the vibrational state of the wind turbine.