An attempt was made to deposit nano-crystalline (or amorphous) diamond films on silicon and 316L stainless steel substrates by electrochemical deposition using a high-voltage pulsed generator. Alcoholic organic compounds with various concentrations of deionized water were used as electrolysis solutions. The surface morphology and crystal structure of the films were examined by scanning electron microscopy and Raman spectroscopy. Adding de-ionized water into the reaction solution can enhance the deposition rate of amorphous diamond films. The crystalline structure analysis has confirmed unambiguously the formation of diamond nano- or submicron-crystals in the deposits. It is believed that the ion H of electrochemical production plays quite similar roles to those that take place in chemical vapor deposition methods of diamond growth.