The invention provides a monitoring method and apparatus of power grid time frequency signals. The method comprises the following steps: acquiring time signals and frequency signals of each synchronization node in a power grid; comparing the acquired time signals with reference time signals to obtain a time comparison result; comparing the acquired frequency signals with reference frequency signals to obtain a frequency comparison result; performing concentrated processing on the time comparison result and the frequency comparison result; and displaying a result of the concentrated processing. According to the invention 1PPS signals and TOD signals of each synchronization node and 2.048MHz signals are acquired by use of a distributed mode, the acquired signals are respectively compared to GPS clock signals and GPS frequency signals as references, such that unified management of time and frequencies in a power system is realized, and the requirement of the power system for time-frequency synchronization service is satisfied.