An open motion control software for a novel selective laser sintering system has been developed to fabricate a three-dimensional porous artificial bone with complex shape. It adopts the library functions provided by a motion control card in Delphi 2006. It focuses on the realizations of control for 'sintering a dot', 'sintering a line' and 'sintering a surface' aiming at the characteristics of selective laser sintering. A problem that the transmission length of interpolation commands can not exceed certain value at a time due to constriction by the register capacity of the motion control card has been resolved. The control software has been successfully used in the experiment of laser sintering for fabricating artificial bone. The results show that the selective laser sintering system has high stability and accuracy.