  We show that in the vacuum inflation model, the gravitational baryogenesis
mechanism will produce the baryon asymmetry. We analyze the evolution of
entropy and baryon number in the vacuum inflation model. The comparison between
dilution speed and the chemical potential may give a natural interpretation for
decouple temperature of the gravitational baryogenesis interaction. From the
result, the mechanism can give acceptable baryon-to-entropy ratio in the vacuum
inflation model.
