The invention relates to a control method and a system of a helicopter rotor, which belongs to the technical field of helicopter operation. The control method is characterized in that the distance changing of a blade is realized by adopting an actuator positioned on the stinger of each propeller boss to drive a flap positioned at the rear edge of the blade, so as to realize the control of a rotor system. The system comprises a demountable flap (1) installed at rear edge of the blade, torque soft propeller bosses (14), an actuator (13) installed on the stinger of torque soft propeller bosses, a flap control mechanism (1) with one end being connected with actuator (13) and the other end thereof being connected with the flap (1), and a test control system (59). The control method and the system have the advantages that the screw piston of each blade can be independently controlled, the structure is simple, the weight is light, the controllability is good, and the reliability and the security are high.