Power quality problems have received more and more concerns in recent years. It has become an important topic in monitoring, controlling, and managing of the power quality. In this paper, the causes of power quality problems, significance of improving the power quality, development status, analysis and control method are mainly analyzed and reviewed. This paper mainly analyzes the advantages and disadvantages of various methods and techniques. With the development of new technology and equipment, the research and development in the field of power quality will have more broad prospects.