Compared with the conventional generation， the capacity credit of wind farms is very low because of stochastic and intermittent characteristics of wind energy and therefore it has great effects on the integration of wind farm into power system. This paper proposes a new optimization model for calculation of the proper integrated wind capacity based on dependent chance programming theory. In the model， the constraints of system safety operation and the electricity generated capacity of wind farms are considered， and the control method for wind farm operation is taken into account as well. The proposed model is suitable for the optimization in uncertainty environment and its utility is validated with the wind farm integrated into IEEE-39 power system.