The real-time measurement of phasor is a difficulty in power system dynamic monitoring, protecting and controlling. This paper uses GPS which can provide the clock signal times accuracy of less 1μs, to establish the same reference for measured TMS320LF2406A embedded DSP chip. The analyzed experimental data improves better precision and veracity. It is a significant evidence for the power systems in rapid, on-line and dynamic monitoring-controlling, and is valuable for practical use.