Disclosed is a method for preparing a directionally solidified TiAl alloy, including: (1) melting and casting a master alloy to obtain a TiAl alloy ingot; (2) processing the TiAl alloy ingot into a sample rod, and placing the sample rod into a refractory metal crucible and then assembling the refractory metal crucible to a directional solidification furnace; (3) vacuumizing the directional solidification furnace, and heating the directional solidification furnace to gradually raise a temperature to exceed a melting point of the sample rod, and conducting heat preservation to melt the sample rod uniformly to obtain a molten TiAl alloy; and (4) directionally pulling the molten TiAl alloy after the heat preservation to allow directional growth to a growth length, stopping the directionally pulling, and taking out an obtained sample to obtain a test rod of the directionally solidified TiAl.