Disclosed are a substrate for a solar cell and a method for manufacturing the same. The method include putting negative and positive electrodes facing away from each other into suspension in which at least two different types of negatively charged cellulose nanofibers are dispersed; applying a voltage across the positive and negative electrodes such that the cellulose fibers are adsorbed onto a surface of the negative electrode; and drying the negative electrode having the cellulose fibers adsorbed thereon.