Abstract: According to the wide-frequency characteristics of electric variables in the power electronized power grid, this paper designs a multi-functional wide-frequency measurement device. Based on high-speed synchronous sampling, the device is optimized to integrate such functions as wide-frequency oscillation detection, synchrophasor measurement and wide-frequency（inter）harmonics measurement. The algorithm models of transient variables, phasors and effective values are synthetically used to improve the monitoring and detection ability of wide-frequency electric variables with different signal structures. Considering both stable and non-stable conditions, the comprehensive detection of power frequency, non-power frequency components and oscillation power in the range of 0～2 500 Hz is realized, which provides targeted data for the research of generation mechanism,propagation path, analysis and control method of wide-frequency electric variables. The multi-functional wide-frequency measurement device realized in this paper has passed the test and been applied in pilot projects.