We formulate a theoretical model for the α decay of well-deformed even-even nuclei based on the coupledchannel Schrödinger equation. The α-decay half-lives and fine structures observed in α decay are well described by the five-channel microscopic calculations. Since the branching ratios to high-spin states are hard to understand in the traditional α-decay theories, this success could be important to interpret future observations of heavier nuclei. It is also found that the α transition to high-spin states is a powerful tool to probe the energy spectrum and deformation of daughter nuclei.