A model based on multiparticle diffusive aggregation is introduced to examine the generated pattern of metal leaf crystals in electrochemical deposition. We simulated the behavior of ions in the solution during electrochemical deposition from two points of view on crystal growth. The first model assumes that the ion in the solution is affected by the force from other ions in order to consider the concentration of ions. The second model is that the ion is affected by the force which corresponds to the applied external voltage from the electrode. Several specific patterns of the crystal growth under an electric field were obtained by a multiparticle Monte Carlo model. The results of the present simulation show that the patterns strongly depend on the force applied to the ions and on their concentration.