In this work, we report a facile directional phosphorization method for construction of hierarchical cross-linked Ni2P arrays, which show a multileveled porous architecture. The basic building blocks are numerous nanoflakes with thicknesses of 15–20 nm, which are self-assembled with each other forming the primary porous mushroom-like structure with 1–3 μm. Impressively, the 3D porous channels run through the whole Ni2P arrays. The secondary nanoflakes consist of interconnected nanoparticles of 10–30 nm and lots of nanopores of 10–50 nm. The electrochemical performance of the as-prepared Ni2P arrays is investigated as cathode of alkaline batteries and demonstrated with higher capacities (127 mAhh g−1 at 2.5 A g−1) and better high-rate cycling stability (123 mAhh g−1 2.5 A g−1 after 9000 cycles) than the preformed Ni(OH)2 arrays counterparts (80 mAhh g−1 2.5 A g−1 and 66 mAhh g−1 after 9000 cycles). The enhanced performance is mainly due to the improved surface area & porosity as well as reinforced electrical conductivity.