Confined crystallization of the micromolded poly(butadiene)-block-poly(ε-caprolactone) (PB-b-PCL) diblock copolymer thin film was studied in this work. The long-range regular ordering of the PCL crystal with crystallographic b-axis parallel to the long-axis of the channel was detected, as indicated by the electron diffraction and grazing-incidence X-ray diffraction experimental results. This preferential crystallographic orientation is mainly because that PCL block crystallization was readily influenced by the geometric effect, then, the fast-growth direction (crystallographic b-axis) was forced to extend along the long-axis of the channel to grow long. Moreover, the substrate induced ordering of the block copolymer restricted the "in-plane" molecular diffusion in the residual layer, and cross-channel crystallization was precluded. Hence, micromolding seems to be a promising method for tailoring the nanoscale crystallization of block copolymer in thin films.