The rotating platform is connected to the satellite by the magnetic suspension joint, which can provide control torque. However, the high-speed rotation of the rotating platform contains huge angular momentum, especially the angular momentum points to the X axis of the orbit coordinate system. There is a complex nonlinear 3-axis coupling attitude due to the influence of the gyro moment generated by the orbital, which makes the high-precision pointing control and rotation speed stability control more difficult. In this paper, the attitude dynamic model of the rotating platform is analyzed deeply, and the kinematics and dynamics equations which are connected by the inertial angular velocity and decoupled from each other are revealed. Then, a dual-loop attitude control method is proposed in this paper. The angular velocity decoupling is realized by the gyro moment compensation in the velocity inner loop, and the high-precision pointing control is achieved by the angular velocity transfer matrix in the attitude outer loop. The rationality and feasibility of the dual-loop attitude control is verified on the dynamic model of the virtual prototype, which can significantly reduce the coupling effect of the 3-axis attitude, and achieve high-precision pointing and precise stability of the rotating platform.