The title compound of isonicotinato lead(II) [Pb(C5H4NCOO)2] has been optimized at B3LYP/LANL2DZ level of theory and calculated results show that the lead(II) ion adopts 4-coordinate geometry. Atomic charge distributions indicate that during forming the title compound, each isonicotinic acid ion transfers -0.452 e to lead(II) ion. The electronic spectra calculations show that there exist two absorption bands and the electronic transitions are mainly derived from the contribution of intraligand π→π* transition and ligand-to-metal charge transfer (LMCT) transition. The thermodynamic properties of the title compound at different temperatures have been calculated and corresponding relations between property and temperature have also been obtained. The calcu- lation of the second order optical nonlinearity was carried out, and the molecular hyperpo- larizability was 3.62365*10-30 esu.