A frequency measurement method is provided, which comprising: sampling a voltage to be measured with a fixed sampling frequency; obtaining a positive-sequence voltage angle change amount for a predetermined operation interval time by using a sampling sample obtained by the sampling and based on a discrete Fourier transform (DFT) calculation; obtaining a frequency offset amount by using the positive-sequence voltage angle change amount; and obtaining a frequency-related measurement value by using the frequency offset amount. A frequency measurement apparatus is also provided. measurement value. This frequency measurement method does not require iterative calculations, and directly obtains frequency-dependent measurement values, thereby responding quickly to frequency changes. In addition, a frequency measurement apparatus is also provided.