Abstract: A space design for the molecule of organic compounds based on the traditional group division method was made, and a topologic group space method for estimating physical properties of organic compounds was proposed by using the group module index to characterize the group position in the molecule. Expressions for estimating enthalpy of vaporization at normal boiling point ΔH_vb and boiling point T_b were established, with the numerical values of relative group parameters obtained by fitting data from 503 and 669 organic compounds respectively. The average percentage deviations of vaporization enthalpy ΔH_vb and boiling point T_b estimation were 0.962% and 1.40% respectively. An extensive comparison between the proposed method and other widely used methods showed that the new method had wider applicability and higher accuracy.