Abstract: Aiming at the real-time change of the relative position of the loader in the wind turbine blade fatigue loading test of two loading sources,a spatial pose monitoring system of two loading sources was established based on D-H coordinate system,and the synchronous excitation control strategy of two load sources was developed based on the recursive least square method. According to the requirements for the direction of the exciting force during the fatigue loading test of wind turbine blades,the spatial position of the two actuators and the angle of the pendulum were monitored by using a laser range finder and an angle sensor respectively,by which a posture monitoring system in absolute space was established. Combining the pose monitoring with the real-time control of synchronous excitation were combined,a controller for synchronous excitation of two load sources was designed based on the recursive least squares method. Finally,an on-site fatigue loading test system was built. The test results indicate that the established synchronous excitation control system of two loading sources was established based on the D-H coordinate system and recursive least square method has the characteristics of greater excitation force,better anplitude stability and system robutness.