This study is concerned with a bifurcation relationship between Taylor vortex flow and wavy Taylor vortex flow. We used three-dimensional numerical calculation. Our concern is a criterion for the estimation of the critical Reynolds number at which the wavy Taylor flow bifurcates to the Taylor flow. We calculated the spatially averaged energy of the bottom vortex of the flow. Before the estimation of the critical Reynolds number, we had to find the criterion for the judgment of the Taylor flow and the wavy Taylor flow. Then we checked the amplitude of the variation of the energy. From the result of the width of the amplitudes of the variations of the energy around the critical point, we established the width of the variation of the energy 0.001 as the standard value. And then we measured the critical Reynolds number between the Taylor flow and the wavy Taylor flow with aspect ratio. Finally the numerical results are compared with the experimental results.