An Explosive Ordnance Disposal (EOD) robotarm is designed toreplace manual operation under the special and dangerous environment.Five stepper motors were needed to control the mechanical arm in this Digital Signal Processor (DSP)system as the Central Processing Unit (CPU) of an embedded control system, and the hardware structure of the mechanical arm was equipped and built with Aluminum (Al) alloy. The arm was under the control of the upper Personal Computer(PC) by the DSP enhanced Pulse Width Modulation (PWM)moduleto drive the step motors, using Matrix keyboard as input and output module，imitating all kinds of movement of the human being.The results of experiment show that the mechanical arm has a strong bearing capacity with rapid adjustment, and there is no oscillation in the experimental process, which meets the designing requirements.