Fine structure and hyperfine structure of Mn2+ in LiNbO3 are analyzed with electron spin resonance (ESR) at room temperature. It is concluded that the zero-field splitting of energy levels of electron spin angular moment between ±12〉 and ±32〉 is Δε1=-587×10-4cm-1, and that between ±32〉 and ±52〉 is Δε2=-2633×10-4cm-1. The anisotropic La nde factors are g∥=21810，and g⊥=20937 The fine structure co nstant is D=-536×10-4cm-1, and hyperfine structure constants ar e A∥=8836cm-1 and A⊥=8120×10-4cm-1. The interaction action of the fine structure is larger than that of the hyperfine structure. In addition, it is worth paying special attention to the fact that two forbidden transitions -32〉12〉 and -12〉52〉 are found.