In this paper, we have investigated the electronic, magnetic, half-metallic and mechanical properties of a new Zr-based equiatomic quaternary Heusler (EQH) compound ZrRhTiTl by means of the first-principles calculations. With the help of the generalized gradient approximation (GGA) in the scheme of Perdew-Burke-Enzerhof (PBE), we reveal that the ZrRhTiTl is an excellent half-metallic material (HMM) at its equilibrium lattice constant 6.70 Å. In the minority-spin direction, a quite large band gap (E bg ) of 0.584 eV and a half-metallic band-gap (E HM ) of 0.137 eV can be observed. For ZrRhTiTl, the formation energy of −1.18 eV and the cohesive energy of 19.35 eV suggest that it is a thermo-stabilized material in theory. The formation mechanism of E HM in the minority-spin direction has also been discussed by considering of the possible d-d hybridization between Zr, Ti and Rh elements. The total magnetic moment of ZrRhTiTl is 2 μ B and it satisfies the famous Slater-Pauling rule M t = Z t -18. Two types of strain, i.e., uniform strain and tetragonal deformation, have been taken into account to examine the magneto-electronic and half-metallic behaviors of ZrRhTiTl EQH compound. Finally, we show that ZrRhTiTl is mechanically stable, ductile and anisotropic.