The research of the power quality of DC power distribution system directly affects the development of the theory and technology of DC power distribution. This paper firstly discusses the distribution voltage level and network structure of DC power distribution system, and then analyzes the voltage fluctuation, flicker, harmonics and other power quality problems in the current DC power distribution system. Then, it focuses on the current domestic and foreign direct current distribution power quality standards, as well as the evaluation system and method applicable to power quality of DC distribution system. After then, it summarizes the current domestic and foreign power quality control solutions for DC distribution system. At last, the research directions of DC power distribution power quality are discussed, which provides reference for the study of DC power distribution power quality in the future. This work is supported by National Natural Science Foundation of China (No. 61374155) and Special Fund for Doctoral Research in Universities and Colleges (No. 20130073110030).