Abstract: According to the developments of power system and consumers,the paper explains the developing and perfecting course of power quality indices,it shows that the development of the indices is basically dependent on researches of conducted disturbance phenomena in power system.The relationships between electromagnetic compatibility（EMC） levels and power quality standards are expounded.The recent developments in the indices are discussed,including variety of the indices,fining and reasoning the index limits,the influences of dispersed generation（DG）,exploring global index and researching economic effect index and so on.