In this article, we present the growth process of cuprous oxide (Cu2O) crystallites on the stainless substrates from an aqueous cupric acetic solution under electrochemical deposition method. Copper acetate (Cu(Ac)2) aqueous solution was used as the electrolyte with the applied potential and reaction time for electrodeposition were varied in this study. Pure Cu2O crystallites of cubic phase with specific surface morphologies were observed under electrodeposited at certain temperature. The specific shape of crystallites electrodeposited at 25 °C is the structure with four identical pyramid-shaped leaves pointing outward and a pointing upward stamen in the middle. The crystal growth type can be classified as the branching growth through a surface diffusion mechanism based on the growth exponent (L ∝ t1/2). The growth of Cu2O crystal is suggested to be surface diffusion of adatoms in dendrite branching growth. A mechanism for the growth of Cu2O crystals under electrodeposition was proposed based on the XPS results. As the temperature increases, the morphology of Cu2O crystals under electrodeposition becomes thinner, but the shape does not change a lot.