Abstract: Brushless DC motor has many advantages such as simple structure, high torque to weight ratio, high efficiency, etc. Hence, it is widely used in aerospace, robotics and office automation. This study presents the mathematical model of Brushless DC (BLDC) motor and shows the values of various technical parameters by using MATLAB/Simulink and study of speed control of BLDC motor drive with Proportional Integral (PI) control. The simulation is carried out for 120° mode of operation. Finally, a PI controller is applied for closed loop under various load conditions.