For an oxide Czochralski crystal growth system, the influence of an active afterheater on the characteristics of the growth process such as temperature and flow fields, crystal-melt interface and the structure of heat transfer have been studied numerically using the finite element method. Several types of heat transfer mechanism, which are convection and conduction within the melt, conduction and radiation within the grown crystal, gas convection and radiative heat exchange between the exposed surfaces, have been taken into account. A comparison between the obtained results demonstrates the role and importance of an active afterheater on the basic parameters of the growth process such as thermal environment and heat transfer structure in oxide Czochralski growth systems.