Tóm tắt: The paper presents an algorithm of self-tuning controller using pole assignment method in controlling speed of DC motor. The parameters of the motor will be online estimated using the Auto Regressive Moving Average Exogeneous (ARMAX) model. And then, a Self Tuning Regulator (STR) is used to control the motor speed. The validity of the STR is verified by simulation results using Matlab/Simulink and also experimented by using DSpace DS1104 Control Card and H-brigde DC-DC converter. The gained results show that the STR can be used to control speed of DC motor.