Abstract: Under the premise of ensuring normal power generation and reliable operation of floating wind turbine,the multi-input and multi-output control algorithm based on state space theory is studied in order to reducing the load of the wind turbine and the motion amplitude of the floating platform. Combined with the design of LQR linear quadratic optimization algorithm,the balance between wind turbine generator performance and floating platform load is found to achieve optimal design. Torque and pitch control design is implemented by DTC and DAC methods,and simulation is performed using FAST software. Compared with the conventional PID control strategy,the load of tower base and floating platform is reduced effectively by this new control strategy. In addition,the state space control has more reflection of interior coupling of the wind turbine and provides a design platform for the subsequent upgrade application of the floating control algorithm.