The concept of double-diffusive convection and its effect on crystal growth are introduced.Double-diffusive covection is a special kind of convection which may occur in a statically stable system of fluid. In some cases of crystal growth, there exist conditions for developing double-diffusive convection. Theories of crystal growth which ignore the effect of double-diffusive convection may lead to obvious deviation from reality. The existing numerical results of crystal growth process coupling with double di...