Abstract: Phasor measurement unit（PMU）, as one of the most effective means of power system dynamic monitoring, can provide data basis for advanced sensing of power system. Therefore, PMU field test and calibration are very important to ensure its operation quality. This paper presented a phasor measurement algorithm, which could provide reference values for error analysis of PMU field tests. Based on the general power signal model, the principle of fundamental phasor estimation in the static and dynamic process of power system was revealed. Then, the spectrum characteristics of phasor algorithm for real-time estimation were analyzed, and a design method of phasor estimation coefficients based on frequency domain displacement of digital low-pass filter was proposed, realizing high-accuracy estimation of fundamental phasor. Furthermore, due to large estimation errors of traditional frequency and rate-of-change-of-frequency（ROCOF） algorithm in oscillation, a frequency and ROCOF estimation method based on least squares filtering characteristics was proposed. The simulation, hardware and field recording data tests show that the measurement accuracy of the proposed algorithm is at least one order of magnitude better than the requirements under the single tests specified in the PMU standard and actual complex working conditions, and thus it can be used for PMU filed testing and calibration.