Abstract: With the continuous development of power-electronized power grid, the increasingly wide-band and complex power grid signals demand higher adaptability and accuracy of measurement algorithms. Therefore, an adaptive measurement method for wideband signals based on windowed interpolation and multiple modulation zoom spectrum analysis is proposed. After selecting the window function based on the characteristics of main and side lobe and interpolation correction process, according to the main-lobe interference of the signal spectrum, the double-spectral-line interpolation algorithm based on four-term fifth-order Nuttall window,and multiple modulation zoom spectrum analysis are separately used for targeted measurements. Finally, the measurement accuracy and stability of the proposed method are verified by simulation comparison and measured data analysis. The results show that the high-accuracy adaptive measurement of harmonics and inter-harmonics with similar frequencies in the range of 0～2.5 k Hz is effectively realized. Higher measurement accuracy and lower computation cost enable it to meet the measurement requirements of a power-electronized power grid.