Abstract: To modified the comprehensive properties of soy protein/polyvinyl alcohol films, the effects of reducing agents on the properties of the films were studied. The tensile strength, elongation, transmittance and water absorption of the films were compared. Furthermore, a vague mathematics model was used to evaluate quality of the films. The results showed that compared with the control, the films with ascorbic acid or L-cysteine exhibited higher tensile strength, but lower water absorption and elongation. The films mixed with L-cysteine exhibited obviously increased transmittance. The tensile strength and transmittance of the films with Na2SO3 were improved significantly, while the elongation and water absorption were decreased unremarkably. With 0.15% Na2SO3, the films exhibited higher evaluation score, and its tensile strength, elongation, transmittance and water absorption were 6.904MPa, 66.076%, 32.310% and 45.695%, respectively. The research contributes to the modification and application of common soy protein/ polyvinyl alcohol films.