Ab inito calculations have been carried out to investigate the structure, phase stability, elastic and electronic properties of the solid solution of Ti3AlC2−xNx (x = 0–2), which were compared with the isostructural and already synthesized end member Ti3AlC2. The substitution of C atoms by N atoms affects the structural parameters a and c. The differences of atomic radius and the bond lengths lead to the changes of structural parameters. Results indicate that Ti3AlCN has the lowest formation energy among the solid solutions, and from the calculation of the cohesive energy, it is found that the stabilities of Ti3AlC2−xNx (x = 0–2) decrease as more N atoms substitute C atoms. The elastic moduli increase as more C atoms are replaced with N atoms. As x increases, Ti3AlC2−xNx solid solutions become stiffer than Ti3AlC2. The calculated density of states suggests that the conductivity of Ti3AlC2−xNx originates from the Ti‐3d contribution and the electrical conductivity becomes higher as more N atoms substitute C atoms.