Abstract: The Square-off centrifugal cascade constitutes an important component of a flexible cascade. In practical engineering operation, during the propagation of fluid disturbances generated by the cascade, the feed pressure at the depleted-end units exceeds the operational limit. To enhance the disturbance resistance of the lean-end units in a stepped centrifugal cascade, static and dynamic hydraulic methods were employed to investigate the impact of the critical parameter α value of the electric control valve on the cascade fluid state. Results indicate that pressure disturbance fluctuations propagate to both sides of the cascade. After re-establishing steady-state conditions, these fluctuations primarily affect the separation stage on the rich-side of the disturbed stage. Similarly, pressure fluctuations caused by flow disturbances propagate to both sides of the cascade, primarily impacting the separation stage on the lean-side of the disturbed stage upon re-establishing steady-state conditions. The value of α affects the cascade's disturbance resistance capability. Through fluid disturbance hydrodynamic analysis, it was found that when α is set to 0, 1, or 2 for each separation stage, the disturbance has a relatively minor impact on the system's final steady-state conditions. With α set to 3 and 4, respectively, when the feed flow rate is increased by 5%, the relative changes in the feed pressure and the depleted-stream pressure at the depleted-end separating stage decrease from 6.02% to 1.96% and from 2.66% to 0.25%, respectively; while those at the enriched-end separating stage decrease from 5.48% to 0.47% and from 2.17% to 0.14%, respectively. Dynamic analysis of pressure fluctuations caused by pressure or flow disturbances in the cascade revealed that, using the largest unit in the cascade as the boundary, setting α=0 or 1 for the separation stage on the rich-side and a=2 for the separation stage on the lean-side minimizes the impact of pressure fluctuations on each separation stage. Under a 5% increase in feed flow rate disturbance, the relative changes of the feed pressure at the depleted-end separating stage decreases from 6.49% to 4.78% and 4.92%; under the disturbance of unit bypass closure, it decreases from 11.97% to 1.46% and 1.56%. These findings provide reference for setting electric control valve parameters in practical stepped centrifugal cascades.