In order to address international competitive pressures, enterprises are continually forced to improve product quality. Improving product quality becomes a main factor in achieving competitive advantage. In this research, we analyze business situations and quality-control techniques, in the form of a case study of a company, to achieve performance improvement. The process is described briefly, as follows. Firstly, the company establishes a quality improvement team and makes a factor analysis defining the relationship between processes. Secondly, the team identifies the quality problems and settles upon an objective and procedures to address the problems. Finally, the team defines some performance index to measure the validity of the quality-enhancement activities. This research is designed to help enterprises to establish a standardized and systematic process for product quality improvement; and this process can be a used as a reference for future technique development.