Abstract: The structure, electronic, phonon and thermodynamic properties of V₂AlX (X=C or N) were investigated by first-principles calculations using PAW method. The structural and electronic properties of the V₂AlX (X=C or N) were discussed. The supercell method of lattice dynamic was utilized to calculate the phonon dispersion curves, and the thermodynamic properties of the V₂AlX (X=C or N) phase at elevated temperatures were predicted by quasiharmonic approximation. The results show that V₂AlC and V₂AlN have metallicity and the replacement of N atoms for C atoms can result in the decrease in the DOS at Fermi level. Both the ternary MAX phases V₂AlC and V₂AlN are dynamically stable.Furthermore, it is found that the thermodynamic properties of V₂AlN are more excellent compared with that of V₂AlC phase, and the bulk modulus of V₂AlN is also higher than that of V₂AlC.