A three-dimensional (3D) Kinetic Monte Carlo (KMC) coupled with embedded-atom method (EAM) (KMC-EAM) has been developed to simulate film growth and morphology evolution of copper layer in Cu2ZnSnS4 (CZTS) precursor during electrodeposition. KMC simulation is an effective tool for researching the growth mechanism, surface microconstruction and film morphology. The multi-body EAM potential, which was based on density functional theory, was employed to calculate the interactions among the metal atoms. As the first electrodeposition stacking layer of the precursor, the structure and morphology of the copper layer is dominant, which directly or indirectly influences the absorber property and solar cell performance. Hence, the influences of the deposition factors, including electrolyte concentration, temperature and electrode potential, on the surface and cross-section morphology were studied. The results demonstrate that the electrolyte temperature and potential have a more significant impact on the film growth compared with the concentration. The lowest roughness with smoother morphology was obtained at the optimal parameters (temperature 338 K, applied potential -0.9 V and concentration 0.5 mol/L). The texture parameters, such as cluster size, and the transformation behavior were selected to describe the film growth evolution during the copper electrodeposition. The cluster size distribution was compared between optimal and original parameters, showing that optimal conditions induce the formation of a smoother film with low roughness, fewer voids, and larger clusters. The comparison between deposition events and diffusion events indicates that the diffusion behavior has a dominant position in controlling the crystal microstructure and film morphology. The film morphology evolution was visualized using a 3D configuration with increasing atoms, and a competing mechanism between layer growth and island growth was proposed. (C) 2016 The Electrochemical Society. All rights reserved.