Abstract: How to balance the frequency regulation performance and the economic cost to reduce or prevent the system's generator-tripping and load-shedding is a crucial challenge in enhancing the reliability of high-ratio renewable energy power systems. To explore the power system source-network frequency cooperative control methods, this paper takes renewable energy generators and LCC-HVDC systems as examples, analyzes the frequency regulation principle and control strategy of the main potential resources, and constructs a multi-dimensional evaluation index system for different frequency regulation measures. Further, combining the ideas of global optimization of parameters based on typical scenarios, disturbances and secondary optimization based on actual disturbances, a source-network frequency cooperative control and parameter optimization method based on the comprehensive effectiveness assessment of frequency regulation measures is proposed. Finally, based on the 2023 data of a UHVDC feeder grid and the frequency test data of a typical renewable energy power station, the PSASP software platform is used to construct a simulation model of the region's power grid after calibration. The validation and analysis of the proposed method is carried out for the typical daytime and nighttime operation modes. The results show that the source-network frequency cooperative control and parameter optimization method based on the comprehensive effectiveness assessment of frequency regulation measures proposed in the paper can significantly improve the frequency support capability of the system while considering the economic cost.