Saline water desalination serves as an important route to increase freshwater supply, while capacitive deionization (CDI) has emerged as a promising technique to tackle this issue. To boost the successful application of CDI, development of advanced electrode materials is vital. Herein, we innovatively designed and synthesized a sophisticated Prussian blue/dimorphic polypyrrole composite for the hybrid CDI (HCDI). Specifically, the nanoparticle-like polypyrrole (PPy) in situ distributed on the surface of stepped hollow FeHCFe nanocubes, while the coexisting nanotube-like PPy interconnected the discrete stepped hollow FeHCFe nanocubes. The introduction of PPy nanoparticles/nanotubes promoted both electron and ion dynamics, and improved the electrochemical activity of FeHCFe. Meanwhile, the FeHCFe nanocubes with concave stepwise architecture on each side offered large accessible contact area for electrolyte, reduced Na