The preparation of high-efficiency electrocatalysts for the oxygen and hydrogen evolution process (OER and HER) using an easy, green, and facile preparation method is crucial for the effective and economical use of clean energy sources. We report here an eco-friendly phytic acid (PA)-assisted phosphidation strategy to synthesize a novel Cu3P decorated on N-doped carbon (Cu3P-NC). Its synthesis involves precipitation of rode-like microstructured Cu-based aspartic acid frameworks (Asp-Cu MOF), chemical etching of Asp-Cu MOF to form PA cross-linked Cu complexes, and a final pyrolysis step to get Cu3P-NC with abundant Cu3P nanoparticles loaded on N-doped carbon matrix. The Cu3P-NC catalyst demonstrates catalytic performances with low overpotentials of 116 and 310 mV at 10 mA cm−2, small Tafel slopes of 61.2 and 69.2 mV dec−1, for HER and OER respectively, and high catalytic durability in 1 M KOH. The as-prepared Cu3P-NC electrocatalyst offers a new viewpoint on developing multi-functional electrocatalysts in the water-splitting process using environment-friendly substances such as amino acids.