Abstract: Mass dispersion research of multi-mass plasma jet has important position in fields like separator or spectrometer. This paper studies the movement trajectory of multi-mass jet flow in inhomogeneous magnetic field and deduces an expression of mass dispersion. Considering the different incident angle and plume, we apply MATLAB to simulate motion trajectory of jet flow, calculate mass dispersion, and compare the result with mass dispersion in homogeneous magnetic field to confirm the effect of jet flow mass separation in this magnetic field. The simulation results show that the mass dispersion of multi-mass jet in inhomogeneous magnetic field is greater than that in homogeneous magnetic field, and that the mass separation of plasma jet can be efficiently realized.