Density functional theory(DFT),complete-active-space self-consistent field(CASSCF)and CASPT2 considering the effect of the dynamical electronic correlation based onCASSCF methods were used to explore the origin of the magnetic anisotropy energy barrier and theexpression of Δξ and ΔA with J and S through investigate the magneto-structural correlations in afamily of FeⅡReⅣ(CN)2 single-chain magnets(SCMs)reported by Long and co-workers(see Fig.1).