Abstract: To quantitatively investigate the impact of compressor fouling on overall aero-engine performance, component characteristics of a compressor under varying fouling degrees were simulated using CFX. Performance deviations relative to the clean state were analyzed to establish a representative dataset of compressor fouling characteristics. This dataset was incorporated into a component-level engine performance model to evaluate the influence of fouling on measurable engine parameters and to reveal their evolution with increasing fouling severity. The results show that compressor fouling induced a forward shift of internal shock waves, promoted earlier and larger flow separation, reduced the effective flow area, and enhanced radial secondary flow and turbulence intensity. These effects collectively deteriorated compressor flow rate and efficiency. As fouling progressed, the high- and low-pressure rotor speeds, exhaust gas temperature, and fuel flow rate of the engine increased gradually, while the compressor outlet pressure decreased. Under maximum and normal takeoff power conditions, the maximum increases in high-pressure rotor speed, low-pressure rotor speed, exhaust temperature, and fuel flow rate reached 1.79%/1.55%, 2.16%/1.87%, 38.51 K/30.75 K, and 27.16 kg·h⁻¹/19.75 kg·h⁻¹, respectively, whereas the compressor outlet pressure decreased by 25.18 kPa and 21.74 kPa.