Abstract: In order to accurately determine the level of interharmonics causing flicker in an electric light source, an inter-harmonic-flicker limit curve of 220 V/50 Hz based on peak fluctuations was established based on the voltage flicker constraints; an analog flicker test was established. Instrument, and then establish the interharmonic-flicker experimental platform, through the experimental platform to draw the interharmonic-flicker limit curve, and use two methods respectively on the 220V/50 Hz fluorescent lamp interharmonic - flicker limit curve Drawing and analysis. The results show that the results obtained by the two methods are accurate and can provide the criteria for whether the interharmonic level reaches the level of flicker caused by fluorescent lamps.