Abstract SMT process is the most critical process to influence products quality in electronic assembly house process. Especially,the solder paste printing control is the key process to determine the yield rate of SMT quality. To own the capability to control quality of solder paste printing is the important thing what assembly house have to face it¡C For the purpose of gaining good SMT yield & solder paste printing stability ,the study use six sigma management technique & procedure (DMAIC--Define¡BMeasure¡BAnalyze¡BImprove & Control) make the main factors of solder paste printing¡Aincluding Printing speed¡BScraper pressure¡BStencil clean frequency¡Ato be the experiment factors of DOE(Design of Experiment)¡CThe DOE minimize the experiment number of times and provide a way of 2 levels factorial design combine RSM(Response Surface Methodology) experiment to get the optimization combination of factors¡¦ levels. Then evaluate how the optimization combination of factor levels to influence the quality of SMT¡C The study final found that there are a surprised & satisfied result on SMT yield improvement caused by optimization combination of factors¡¦ levels which 2 levels factorial design combine RSM experiment generated. It can provide the procedure & methodology for SMT assembly house reference to improve yield rate .