本研究運用六標準差專案手法之流程步驟DMAIC (Define、Measure、Analyze、Improve、Control)，針對個案A公司被UL稽核到之主要不符合事項作為研究對象。研究結果顯示，個案A公司在透過六標準差之管理活動，找出了關鍵因素，並分析出其主要之變異源。並且，主要不符合事項在透過新流程的導入後，獲得顯著的改善;製程能力由改善前1.44 σ提升至2.65σ，亦為公司在財務上帶來實質之效益。 Due to the harsh industrial environment, the enterprises are forced to join the“Low-profit”competition in order to obtain clients’new orders, and higher quality is even requestd by the clients. Hence, enterprises should implement the new quality managerial models by reducing the product manufacturing cost and quality cost as well as impoving product quality in order to strengthen the competitive advantage. The concept of “Six Sigma” was introduced and discussed in 1980s by mainly adopting quality improvement techniques. It emphasizes the application of scientific methods plus data-driven. Six sigma management aims to the process improvement for the existing problems so as to increase the product yield rate and then satisfy customers’demand. It also achieves cost savings and financial benefits for the enterprises. This research direction is built under the basis of the trend of quality improvement by sorting out the theories and documents with relation to the concept of “Six Sigma”. Starting from the comparison of the definitions and techniques of Total Quality Management (TQM) and Six Sigma (6σ), this research also further comprehends the correlations and differences between these two managemrial models, and then determines the improving method. Besides, the related UL service programs are also introduced in order to provide the foundation for this thesis. This research aims to solve the problem of non-compliance items spotted by UL in company A based on the procedure of DMAIC (Define, Measure, Analyze, Improve, Control) of“Six Sigma”. The result shows that after introduction of the concept of “Six Sigma”, company A finds out the root cause of the variations. In addition, a significant improvement on the non-compliance items is obtained by implementing the new manufacturing process. The manufacturing capacity has been improved from 1.44σ to 2.65σ. The company also obtains real benefits in financial aspect.