The invention relates to a detection method of a voltage flicker. The detection method specifically comprises the steps of: acquiring a grid voltage, acquiring a high-sampling-rate grid voltage effective value sequence XH and a low-sampling-rate grid voltage effective value sequence XL; calculating original frequency spectra of the XH and the XL by utilizing windowing FFT separately, and correcting frequencies and amplitude values of the original frequency spectra by utilizing a frequency spectrum correction algorithm to obtain corrected frequency spectra SH' and SL'; and calculating a short-term flicker value and a long-term flicker value by utilizing the corrected frequency spectra SH' and SL' obtained in the step 2. By adopting double-sampling-rate Fourier analysis, the detection requirements for low-frequency flicker signals is satisfied by means of Fourier analysis of the low-sampling-rate sequence, and the analysis requirements for high-frequency flicker signals is satisfied by means of Fourier analysis of the high-sampling-rate sequence, thereby significantly reducing the voltage flicker calculation load and requirements for storage space. In addition, by adopting a method of carrying out interpolation fitting on dominant frequency and the short-term flicker value, the voltage flicker measurement precision is improved.