Based on approximately linearized system model， a linear quadratic regulator（LQR） DC current modulation controller for multi-infeed HVDC system is presented. In power system， generally， using rotor angles as feedback signals can change oscillation frequencies， and using rotor speed as feedback signals can change the oscillation damps. Based on the above two characteristics， three measures are presented to simplify the implementation of the proposed LQR controller. Without degradation of good performance， for each DC link， the simplified LQR controller only requires the adjacent generators’ relative speeds as modulation signals. Thus the communication burden is greatly relieved because less information is needed to transmit around the system. Simulation results on a 10-machine 39-bus AC system with 5 DC links located in it show that the simplified LQR modulation controller is effective.