The invention discloses a method for growing a semi-metal epitaxial magnetic tunnel junction. The method comprises the steps of: epitaxially growing a Co2FeAl layer, an MgO layer and a Co2FeAl layer on a GaAs substrate by using an MBE technology to form a semi-metal magnetic tunnel structure, wherein Co, Fe and Al are evaporated by thermal evaporation beam source furnaces in the growth process, and the evaporating temperatures of the three thermal evaporation beam source furnaces are respectively controlled to control the deposition rates of the three elements; performing annealing on the GaAssubstrate prior to growth, performing annealing on each Co2FeAl layer after each Co2FeAl layer is grown, introducing the oxygen into an MBE cavity after an Mg layer is grown and oxidized to form an MgO film, and finally growing an Al layer with a thickness of 3nm for covering. The MBE technology is employed to accurately control the beam current to achieve the modulation of alloy film components,and the RHEED and the in-situ heat treatment are employed to make the surface of the sample flat and form a single crystal structure so as to obtain a high-quality semi-metal epitaxial magnetic tunnel junction.