The contradiction between the significant economic effects of wind turbines and the frequent errors that cause a series of problems, including low utilization rate, long repair rate time and severely economic losses and so on, is becoming increasingly conspicuous. With applying composite gray theory to wind turbine the scientific, reasonable and allsided method for effectiveness evaluation is proposed. According to the characteristic of structural parameters and technical parameters for wind turbines, it can be divided into many relevant factors in terms of effectiveness of wind turbines power. Moreover, the system of evaluation index is structured. With applying gray theory and analytic hierarchy process to effectiveness evaluation, the effectiveness is evaluated amply and comprehensively. The test results indicate that the method can effectively deal with the ticklish question of information handing, optimize the distribution and arrangement and provide decision and deployment unit with decision basis.