IEC flickermeter cannot accurately measure peak fluctuation flicker caused by high-frequency interharmonics， therefore， an improved hybrid time and frequency domain method for the flicker measurement caused by high-frequency interharmonics is presented here. In the time domain， a synchronous demodulation method is used to replace square demodulation of the IEC method to extract fluctuant signal caused by high-frequency interharmonics. Firstly， a simple method is used to extract the synchronizing fundamental signal， then ratio operation is performed to odd power of the signal to get synchronous harmonic signal set， and finally the high-frequency interharmonic signals are demodulated through operating the original signal with harmonic signal set. In the frequency domain， the recursive Fourier transform is used， and then， different frequency components are weighted according to a visual sensitivity curve. This process is used to compensate for the defect that visual sensitivity weighting filter cannot accurately simulate the visual sensitivity curve. Corresponding algorithm model is built in Labview， experiments are conducted to prove that the proposed algorithm can accurately detect the flicker caused by high-frequency interharmonics. Finally， the interharmonics flicker curve caused by a single interharmonic and a pair of interharmonics is obtained through the proposed method， and the characteristics of interharmonics flicker limits of different frequency bands are analyzed.