Abstract: Bubble-point vapor pressures along with the coefficients of Antoine equation correlation were reported for 22 hydrocarbon fuel fractions with different true boiling temperature ranges to investigate the relationship of vapor-liquid phase equilibrium constants between wide and narrow fuel fractions. The fuel samples were originated from crude oils with the initial atmospheric boiling temperature from 348.15 K to 623.15 K. The vapor pressures at the range from about 8 kPa to 101.3 kPa were measured by using a specially designed inclined ebulliometer with a pump-like stirrer on the basis of the principle of quasi-static method. On the basis of a wide fuel fraction assumed to be composed of several pseudo components (narrow fuel fractions with the boiling temperature range of 25 K), the vapor-liquid phase equilibrium constants of different pseudo components at different bubble-point conditions were calculated. The VLE constants were also correlated with the boiling temperatures of the pseudo components, the phase equilibrium temperature and pressure. A generalized equation was obtained with an overall absolute average deviation of 4.5% from the experimental values tested by 180 datum points at the pressure range from 8 kPa to 101.3 kPa and the normal boiling temperature range of fuels from 348.15 K to 623.15 K, which can give reasonably satisfactory results in engineering calculation.