The energy budget in the wave-number domain is calculated for an Atlantic-Europe blocking process during October to November 1980. The relationship is exam-ined in detail between the energy evolution of ultra-long waves (wavenumber 1-3)and synoptic-scale waves (wavenumber 4-10) and the foundation, maintenance andbreakdown of the blocking high. Results indicate that the kinetic energy of ultra-longwaves controlling the blocking originates mainly from the conversion of baroclinic avail-able potential energy and the nonlinear cascade transfer of the kinetic energy of synoptic-scale waves while the available potential energy of ultra-long waves mainly from theconversion of the zonal mean available potential energy. The nonlinear interaction of thecomponents on different temporal scales also plays an important role in the foundationand maintenance of the blocking high.