Abstract: To address problems including efficiency decline, cavitation, vibration and noise frequently occurring in centrifugal pumps transporting high-viscosity multiphase crude-oil-containing sewage on offshore oil platforms, this paper proposes an optimization scheme for key impeller design parameters to improve energy performance and operational stability. Combined with numerical simulation and theoretical analysis, this paper investigates the influence mechanism of blade number on pump energy characteristics. Performance tests and flow-field simulations are carried out to verify the improvement of multiphase-medium adaptability and hydraulic efficiency brought by parameter optimization. The research offers important design references for efficient, low-noise and reliable operation of centrifugal pumps for offshore crude-oil-containing sewage transportation, and possesses great engineering value for guaranteeing the stability and energy-saving performance of marine oil-gas production systems.