A metal laser rapid prototyping (Three Dimensional (3D) printing) machine based on using Program Multiple Axis Controller (PMAC) for motion is designed. PMAC motion controller was used to control all motors motion and Input/Output(I/O) data gathering. Furthermore，the hardware and software structure of this system were also discussed. Considering very heavy influence of position precision of the motor driven work platform on quality of the prototyping parts，a PMAC position precision compensation technology was researched and applied to optimize for imperfections in the leadscrew of mechanics. Good effect is implemented in the prototyping machine, which shows a welldesired performance.