Abstract: In order to improve performance of the X-ray streak camera cathode, we propose a new fabrication method of X-ray streak camera cathode, the benefit of this method is that the thickness of the substrate film using polycarbonate as raw material can be reduced to 300 nm. Thus the spectral response sensitivity of the cathode can be improved as the absorption to incident X-ray of the substrate film can be reduced. Absolute calibration of Au and CsI cathodes made by this method was carried out in Beijing Synchrotron Radiation Source (BSRF). Spectral response sensitivities of the two kinds of cathodes were obtained in the energy range of 60-5500 eV. Calibration results show that CsI cathode has a high spectral response sensitivity in the whole energy range of 60-5500 eV, and the spectral response sensitivity in carbon absorption edge is only about 9/10 lower.