Abstract: In order to meet the requirement of frequency regulation and to enhance the power quality, the real measurement of primary frequency regulation function of grid\|connected units and its input are important. The performance of primary frequency regulation of large pumped storage units is analyzed according to experiment results, and the parameters of governor are optimized based on analysis results, which bring the primary frequency regulation of units into work to meet the requirement of power grid. The optimized parameters can meet the relative requirements of the performance of primary frequency regulation for power grid based on security of units operation.