The response of an I=3/2 nuclear quadrupole resonance(NQR) system to a comb-pulse train is calculated by means of the density matrix theory and computer simulations. The influence of the off-resonance( including inhomogeneous line broadening) upon the comb-pulse NQR powder line shape is also discussed in detail. It was found that under the condition of small off-resonance, the comb-pulse NQR spectrum is analogous to that obtained with the two-dimensional nutation NQR technique, but the time required to perform the comb-pulse experiment is nearly two orders less than that required by the latter.