A comprehensive prediction of the electromagnetic, hydrodynamic and noise characteristics of a linear magnetohydrodynamic (MHD) thruster is achieved based on the numerical simulation method which combined the electromagnetic-flow multi-fields coupling with the flow-induced noise. The key influencing factors of the propulsion performance and the mechanism of noise generation are revealed. The results show that: (1) Non-uniform field distribution of both the current density and electromagnetic force in the MHD channel are born due to the leakage electric field and magnetic field. Especially at the junction of the electrode and insulation wall, the axial electromagnetic force is 2 times larger than that in the center. (2) The main influence on the hydrodynamics is that the pressure potential energy is remarkably increased, while the trapezoidal velocity profile is formed. (3) The noise radiation intensity is significantly amplified, 10 dB higher of the sound pressure level at most frequencies of 200–1k Hz is observed because of the MHD coupling effect.