The coupling between fiber optical taper and CCD is the critical technique for the integrated taper assembly image intensified sensors. Compared to a lens-coupled CCD camera system, the CCD camera coupled with fiber optical taper has higher collection efficiency, and yields significant gains. So fiber optical taper plays an important role in the integrated devices. The coupling efficient between fiber optical taper and CCD exerts an influence on the signal-to-noise ratio of the integrated devices, but the effective transmission of taper has influence upon the coupling efficient. In this paper, the core-packing fraction of taper has been calculated precisely according to the virtual structure of fiber optical element, the attenuation and losses of the light energy transmitted through fiber taper have also been analyzed and deduced according to the ray mode transmission characteristics in the taper. Finally the effective transmission of taper was deduced, and an objective measurement of the effective transmi