In this paper computational calculations were performed based on the density functional theory DFT, to investigate the structural, electronic and magnetic properties of CuAl1-xCrxS2 (x=0.0, 0.50 and 1.00) alloys. Pseudopotential method was used, as is implemented in the Quantum-Espresso code. We found that the alloys crystallize in a tetragonal structure belonging to space group 122 (I-42d) with lattice constants a=5.290Å, c=10.378Å for x=0.5 and a=5.283Å, c=10.366Å for x=1.00. These values are in good agreement with experimental results. Additionally, we found that the alloys possess an antiferromagnetic behaviour with magnetic moments 4,20μβ/cell and 4,05μβ/cell, respectively. From the analysis of the density of states, it is clear that the alloys have a half-metallic behaviour due to the Cr-d and Cu-d states crossing the Fermi level. This compounds can be used in spintronic.