Abstract: To address the challenge of impeller clogging due to entangled impurities in submersible sewage pumps, the 200WQ400-14-30 semi-open double-blade model was numerically investigated to analyze the influence of blockage position on its performance. The results indicate that: （1） Performance degradation intensifies with blockage proximity to the outlet: Compared to normal conditions, outlet blockage increases power by 4 kW and reduces efficiency by nearly 13%. （2） Blockage causes a significant increase in the radial force on the impeller, with the mean value rising from 104 N to 322 N and fluctuations intensifying. The resultant force direction shifts from symmetry to eccentric aggregation in the fourth quadrant, consistently deviating from the blockage location. The overall blockage process exhibits enhanced low-frequency excitation dominance. This study reveals the influence mechanism of blockage position on hydraulic excitation, providing theoretical support for anti-clogging impeller design and operational stability optimization.