With wave equation of electromagnetic wave and motion equation of electron in magnetized plasma, the dispersion equation of propagation of electromagnetic wave is obtained, through which the refractive index and inversebremsstrahlung absorption coefficient of magnetized plasma are derived. It can be found that the cut-off wavelength ofplasma decreases obviously as the intensity of external magnetic field increases, resulting in the low frequency electromagneticwave cannot pass through the plasma. For electromagnetic waves with around 1μm wavelength, the refractive indexand inverse bremsstrahlung absorption coefficient of plasma barely change with the intensity of external magnetic field. Forelectro-magnetic waves with around 10μm wavelength, the refractive index of plasma decreases as the intensity of externalmagnetic field increases, while the inverse bremsstrahlung absorption coefficient of plasma increases with the rise of intensityof external magnetic field. The theoretical analysis and numerical results reveal the mechanism of electromagneticwave propagation in magnetized plasma, which has theoretical significance in study of effect of external magnetic field andplasma on laser propagation in laser hybrid welding process.