Bloom-Gilman quark-hadron duality of nuclear spin structure function is studied by comparing the integral of g1 from perturbative QCD prediction in the scaling region to the moment of g1 in the resonance region. The spin structure function in the resonance region is estimated by the parametrization forms of non-resonance background and of resonance contributions. The uncertainties of our calculations due to those parametrization forms are discussed. Moreover, the effect of the Δ(1232)-resonance in the first resonance region and the role of the resonances in the second resonance region are explicitly shown. Elastic peak contribution to the duality is also analyzed.