In this paper, spectral response characterization on S-25 and New S-25 photo-cathodes are studied. Since photocathode has thicker pliotocathode thickness, higher photocathode structure parameter and spectral response cut-off wavelength, phot oca-thode sensitivity between 850 and 1000nm is improved. The improvements repres ent the superiority of New S-25 photooathode as well as a new direction of multialkali photocathodes.