Cu2ZnSnS4 (CZTS) films were formed by an electrospray method, and the effects of annealing temperature on the properties of CZTS films were investigated. All CZTS films exhibited a kesterite structure with a preferred orientation of (112), (220) and (312), and did not show non-CZTS phases according to the annealing temperature. The grain size of CZTS films increased substantially in the temperature range of 300-450 °C, and the optical band-gap (Eg) of the films with increasing temperature decreased from 1.71 eV to 1.42 eV. Consequently, single-phased CZTS films were acquired without annealing process by electrospray method, and the annealing process improved the optical and structural properties of CZTS films. These results demonstrated that the CZTS films developed in this study has promising potential for the formation of high quality CZTS thin films in thin-film solar cells.