In order to optimize the operation patterns of Henan power grid after putting the 800 kV UHVDC from Hami to Zhengzhou into operation, the relationship between DC system control modes and voltage stability of receiving-end power network is analyzed in detail, and the regularity of different control modes impacting the voltage stability of AC bus at converter station is revealed and simulated based on the planning data of Henan power grid in 2014. Simulation results show that the Ha-Zheng UHVDC taking CP-CV control mode i.e. constant power at rectifier side and constant voltage at inverter side will be conducive to voltage stability of receiving-end power network; after putting Ha-Zheng UHVDC into operation, the operation patterns of multi-channel transferring HVDC power from Henan to Central China Grid combined with partly internal consumption are favorable to improve the static voltage stability. The analysis results provide theoretical basis for future optimizing operation and scheduling of Henan power grid.