To reduce the low-frequency fluctuation and radiated noise of pump-jet propulsor (PJP), by adjusting the pre-whirl angles including inlet angle, outlet angle, and stagger angle of a given PJP, this paper numerically analyzes the hydrodynamic performances of the PJP with limited range of stator pre-whirl angles. Results showed that the thrust, torque, and peak efficiency all increased with increasing pre-whirl angle, and the stagger angle had the greatest effect, followed by the outlet angle, and the inlet angle was the least. Through analysis of the rotor force fluctuation in frequency domain, it was found that the force fluctuation of single rotor was affected by stator, and the corresponding frequency was stator blade passing frequency (BPF_s), with the maximum amplitude at 1BPF_s, while the frequency corresponding to the total thrust was jointly affected by rotor and stator, with the maximum at 4BPF_r. The standard deviation of surface pressure on blades was analyzed, and the region with the highest fluctuation was near the leading edge and tip of rotor, while that for stator located around trailing edge. Further analysis on pressure fluctuation characteristics of probes around rotor and stator was carried out. The obtained major frequency was 1BPF_r, and the most intense pressure fluctuation was observable at medium and high radius of PJP's wake. Overall, the low-frequency pressure fluctuation of PJP was increasing with the increase in pre-whirl angle, yet the influence law of three methods of adjusting pre-whirl angles was different under positive and negative angles. In addition, the phases of probes at same axial position but different radial positions near the leading edge of rotor were studied. Results showed that the effect of outlet angle and stagger angle was more significant, and the phase difference was obviously different according to the sign of pre-whirl angles.