With the graphic method and nolinear programming, twelve structural - type properties and condensed - type properties of homologous straight- chain alkanes, such as the highest bonded molecualr orbital energy, the lowest bonded molecular orbital energy, ionization energy, half - wave potential of oxidation, normal boiling point, normal melting point, critical pressure, critical temperature, density, refractance, surface tension and vicosity, have been developed. The results show that strutural - type properties and condensed - type properties of straight - chain alkanes generally obey the homo...