The influence of laser power,scanning speed,thickness of single layer and preheat temperature on molding quality in selective laser sintering (SLS)are studied. With manufactured specimen pieces by Molding machine AFS-450 of SLS,the combination of the prototyping sintering parameters are optimized . The result and solution of the experiment are the preheat temperature of 100℃,the scanning speed of 2000 mm/s,the laser power of 24W,the thickness of single layer of 0.2mm for ABS,and the prototyping quality improving greatly.