To meet the demand for accurate measurement of liquid hydrogen mass flow, a finite element numerical model of a Π-shaped Coriolis flowmeter was established using the COMSOL Multiphysics platform. Numerical simulations were conducted with water as the working fluid, and the reliability of the model was verified by comparing the simulation results with theoretical predictions. Liquid hydrogen was used as the working fluid to systematically investigate the measurement characteristics of the Π-shaped Coriolis flowmeter. The effects of excitation frequency, detector position, and exciter length on phase difference and amplitude were analyzed, and the influence of temperature variations on the measured phase difference was also explored. The results show that: 1) regarding excitation frequency, using the wet modal frequency as the excitation frequency yields larger amplitudes, which are beneficial for signal acquisition and processing; temperature changes affect the natural frequency by altering the material properties of the measurement tube, thus requiring corresponding adjustments to the excitation frequency; 2) the detector position significantly influences the phase difference—the phase difference gradually decreases as the detector moves away from the fixed end; for the Π-shaped tube model, the optimal detector location is at the junction between the bend and the straight inlet/outlet sections, where high detection sensitivity and stronger signals can be achieved; 3) the impact of exciter length on the flow coefficient is minimal, but it is positively correlated with vibration amplitude; longer exciters produce higher amplitude signals, though practical structural requirements must be considered in the design; 4) temperature variations alter both the physical properties of the measuring tube and those of liquid hydrogen; the density of liquid hydrogen has the most significant effect on the phase difference, while the elastic parameters of the measuring tube also play a role; the density of the measuring tube and the viscosity of the fluid have negligible impacts. The findings of this study provide a theoretical and modeling foundation for optimizing the structure and improving the measurement accuracy of Coriolis flowmeters for liquid hydrogen.