According to the international standard of German GL 2010, a wind turbine of 850 kW is applied to the corresponding wind power generation unit and its situation of pneumatic rated power and sympathetic vibration is analyzed with Bladed software. The result verifies the reliability of wind turbine in operation. Further, after all the wind regimes in GL standard are calculated and analyzed comparatively, the extreme wind regimes which mainly influence the aerodynamic performance of the wind blade are obtained, namely, Dlc4.2b, Dlc1.3a, etc. Later on, the evaluation criteria of wind turbine blade taking the load of blade root as standard are established and implemented with the built-in demo data of Bladed software to testify its generality. Then based on the above evaluation criteria, extreme loads of the 850 kW’s blade root is computed and it’s found the extreme swing load is 353 663 N·m, which is 2.5% lower than its designed value. The result verifies the security of the blade in operation and the reliability of the evaluation criteria.