The ΔH_^θf,298 and ΔG_^θf,298of 56 solid inorganic compounds were first estimated by the group contribution method. The estimated ΔH_^θf,298 and ΔG_^θf,298 were compared with the literature values, and the absolute value of the relative error is within 4%. Based on the group contribution method, a mathematical model for estimating LiNi_xCo_yMn_zO₂ cathode materials ΔH_^θf,298 and ΔG_^θf,298 was constructed, and LiNi_0.6Co_0.2Mn_0.2O₂, LiNi_0.5Co_0.2Mn_0.3O₂, LiNi_0.8Co_0.1Mn_0.1O₂ and LiNi_1/3Co_1/3Mn_1/3O₂ were constructed, ΔH_^θf,298 are -705.39kJ.mol_^-1, -703.90kJ.mol_^-1, -695.67kJ.mol_^-1 and -705.17kJ.mol_^-1; ΔG_^θf,298are -647.98kJ.mol_^-1, -640.04kJ.mol_^-1, -631.10kJ.mol_^-1 and -642.41kJ.mol_^-1, respectively.