Based on coordinate transformation and mechanical analysis, load transformation between blade root and rotor coordinate system for wind turbine is derived.And an analysis model closer to actual working condition is established.Taking a 5 MW wind turbine as analysis object, analyzing results of the new model, traditional simplified model and GH Bladed model are compared, and results are good enough to validate this new model has higher reliability and accuracy.In addition, based on analyzing to load component, through access to instance data of each factor in process of coordinate transformation, the impact of each factor can be accurately analyzed, which is of great significance to control and reduce load.