Abstract: In order to ensure the safe and stable operation of hydropower systems, improve the safety and the multi-energy complementary ability of power grids, starting from the primary frequency modulation effect of pumped storage units, we constructed a simulation model of dual and three units of different pipeline layout forms considering hydraulics, mechanical and electrical subsystems.Considering different control parameters, different initial operating conditions, different load disturbance and other potential factors, unit regulation quality considering different pipeline layout forms was evaluated, revealing influences of pipeline layout on the unit frequency regulation performances.Based on the analysis results, we summarized the potential risks in the process of frequency regulation.Finally, the intuitive fuzzy analytic hierarchy process, factor analysis method and improved radar chart method were introduced to realize the comprehensive performance evaluation of primary frequency modulation of the pumped storage units by considering the speed stability, hydraulic system stability and damping characteristics of the unit as indexes.The results are of great significance for ensuring stable operation of pumped storage units as well as improving safety of power grids and multi-energy complementary ability.