A new estimation method (CSGC) was proposed by combining corresponding state principle with group contribution method and a new vapor pressure equation (CSGC - PR) was developed with this method. Contribution values of 88 groups were obtained by correlating 5255 vapor pressure experimental data of 350 substances including saturated hydrocarbons

unsaturated hydrocarbons

cyclohydrocarbons

aromatics

oxygen compounds

sulfurcompounds

nitrogen compounds

halohydrocarbons

etc. The new model is suitable to a wide variety of hydrocarbons and has good accuracy. Predicted results for vapor pressures of 28 substances (on database) show that the CSGC -PR equation is superior to the corresponding state equations. Satisfactory results were also obtained in predicting vapor pressures of nonpolar substances under a high pressure.