A new nanocomposite consisting of ZnO nanowire turf‐coated Bi2O3 plates was synthesized using a method combining a chemical bath and hydrothermal crystal growth through sputtering ZnO seed layer‐assisted growth. Structural analysis revealed that highly crystalline, high‐density, one‐dimensional (1D) ZnO crystals were uniformly coated on the organized two‐dimensional (2D) Bi2O3 plates with a single β phase or dual α/β polymorphic phases. The Bi2O3–ZnO composites exhibited enhanced absorption properties in the ultraviolet and visible regions compared with pristine Bi2O3 and ZnO. Furthermore, the Bi2O3–ZnO composites exhibited higher photoactive performance than that of the pristine Bi2O3 and ZnO because of the low recombination rate of photoinduced electron−hole pairs caused by the vectorial transfer of electrons and holes between ZnO and Bi2O3 and the substantially increased surface area of the unique composite morphology. The ZnO nanowire turf‐coated Bi2O3 plates with a α/β‐Bi2O3 matrix exhibited photoelectrochemical and photocatalytic properties superior to those of the composite with a single β‐Bi2O3 matrix. The coexistence of α/β homojunction in the Bi2O3 matrix and the abundant heterojunctions between the ZnO nanowires and Bi2O3 plates substantially enhanced photoexcited charge separation efficiency. Growing high‐density 1D ZnO on 2D Bi2O3 via a combination methodology and crystallographic phase control provided a promising material design route for nanocomposite systems with high photoactivity for photoexcited device applications.