Abstract: 11 molecular mechanics(MM)parameters and 13 quantum chemical parameters of Pinacidil-type cyanoguanidine, thioureas and imine-derivated compounds were calculated by MM2 method and CNDO/2 method respectively. Two significant correlation equations between the vasodilator activity of these compounds and the structural parameters mentioned above were established by stepwise regression analyses. lg1/IC50(1)=0.1259+1.7111DM+0.0930PSn=16,R=0.7444,S=1.3121,F=8.0771>F2,13(α≤0.01)=6.70;lg1/IC50(2)=1.2114-28.7840QN(1)+0.1265DM(n=16,R=0.7658,S=0.4616,F=9.2182>F2,13(α≤0.01)=6.7. The QSAR equations show that the vasodilator activity of these compounds increases with the increase of dipolemoment(DM) , ratiovalue(PS) of solvent-accessible hydrophobicsurface area of molecule to the hydrophilic, and of absolute value of electronic charge of pyridinenitrogen. The results also suggest that the vasodila to ractivity of these compounds is mainly dependent upon the distribution of electronic charge and the hydrophobicity of molecules.