The invention provides a torque and variable-pitch decoupling control method for a wind driven generator set, a controller and a system thereof. The method comprises the following steps: calculating a variable-pitch control bias value in an area where a torque controller plays a leading role, adjusting a generator rotation speed reference set value of a variable-pitch controller, and outputting a corresponding pitch angle set value; calculating a torque control bias value in the area where the variable-pitch controller plays a leading role, adjusting the generator rotation speed reference set value of the torque controller, and outputting a corresponding electromagnetic torque set value. The controller comprises a variable-pitch bias area calculating module, the variable-pitch controller, a torque bias area calculating module and the torque controller. The system comprises a decoupling controller, a variable-pitch system, a current transformer, a pitch angle position sensor and a rotation speed sensor. According to the invention, decoupling for the torque controller and the variable-pitch controller of the wind driven generator set are achieved so as to improve performance of two controllers in respective action area, and avoid disturbing control effects with each other, thereby making good use of the advantages of variable-speed and variable-pitch wind driven generator sets.