The detonation performance parameters of different types of explosives were predicted with VLWR (Virial-Wu-R) code, and three sets of solid carbon parameters, including graphite parameters, diamond parameters and liquid carbon parameters were used. The component of equilibrium state for detonation products was determined based on the minimum Gibbs free-energy principle. The free-energy calculation of solid carbon in original VLWR program was modified by selecting the solid carbon phase in the calculation process. The Gibbs free-energy of graphite, diamond and liquid carbon were calculated by revised VLWR program. The most likely phase of carbon at C-J point for the detonation products was determined from three kinds of carbon phases, then the detonation parameters of explosive were calculated based on the minimum Gibbs free-energy principle. The detonation parameters of dozen CHNO explosives, including RDX, HMX, PETN etc were calculated with carbon phase selection. Results show that the calculated results were in good agreement with the experimental ones.