A method of manufacturing a substrate for a photovoltaic cell, in which the high optical characteristic in a long-wavelength range available for the photovoltaic cell can be maintained, and at the same time, the amount of hazing can be increased. The method includes the step of forming a zinc oxide (ZnO) thin film layer doped with a dopant on a transparent substrate, and the step of controlling the surface structure of the zinc oxide thin film layer by etching the zinc oxide thin film layer using hydrogen plasma.