The influence of fiber grating dispersion ripple on CATV signals is analyzed and the power of intermodulation terms fallen into the range of 50 MHz～550 MHz is estimated about 10%～50% of the total power of all the intermodulation terms. In order to restrain the amplitude of dispersion ripple, the refraction index change of fiber gratings should be made to rise from zero to its maximum value gradually. 10 cm-length fiber gratings with apodized refraction index profiles of raised-cosine or tanh(4z) shape can be used in CATV systems in theory. The longer the fiber gratings are, the smaller period of dispersion ripples they have, and subsequently the much less the influence on CATV signals. It is found that the fiber gratings with raised-cosine tapered profile have smaller dispersion ripple amplitude than those with tanh(4z) profile.