Abstract: With the gradual replacement of traditional synchronous units by power electronic devices, the power system has gradually shifted from "physical synchronization" to "control synchronization". Therefore, the stability issues caused by the inverter control link have received widespread attention. Previous studies have shown that in hybrid multi-infeed systems with grid-following or grid-forming devices, grid forming devices can suppress sub-synchronous oscillations caused by grid following devices in weak current networks. However, they are prone to low-frequency oscillations in strong current networks. At present, the power system is still in the transition stage towards a "dual high" system and the quantitative evaluation of the grid voltage support ability of grid-following or grid-forming converters in hybrid multi-infeed systems under different grid strengths and the coordinated optimization configuration method in multi-frequency bands are still unclear. Therefore, this article first conducts modal analysis on the grid connected system of single-infeed grid-following or grid-forming converters, exploring the distribution characteristics of the dominant oscillation modes corresponding to grid-following or grid-forming converters under different grid strengths in multiple frequency bands and forming a coordinated and optimized configuration principle for hybrid multi-infeed systems. Secondly, based on the idea of modal decoupling, an equivalent approximation is made to the stability of the hybrid multi-infeed system, revealing the relationship between the damping ratio of the dominant oscillation mode of the system and the quantitative indicators of the support capacity of the grid-following or grid-forming under multi-frequency bands. Then, a coordinated and optimized configuration method is proposed for grid-following or gird-forming oriented towards improving system small disturbance stability. Finally, the correctness of the proposed equivalent approximation method for hybrid multi-infeed systems and the effectiveness of the coordinated optimization configuration method are verified through simulation examples.