Abstract: The most authentic and granular information on behaviors of power systems are contained in the voltage and current waveforms. Synchronizing waveforms measured from different locations would help understanding dynamic characteristics of the power system, and monitoring, protecting, and controlling power systems and apparatuses. Firstly, from the aspects of monitoring system composition, data characteristics, advantages and disadvantages, this paper compares the existing power grid monitoring methods along the context of the development of monitoring methods, clarifying the difference between synchronized waveform and traditional grid measurement data. Secondly, focusing on the fields including grid harmonics, broadband oscillation, fault identification and comprehensive grid perception, the limitations of traditional monitoring methods are clarified, and results of researches on application of synchronized waveform data are reviewed. It further discusses application limitations and future research directions.