We present a study of improving the gravitational waveforms of the coalescing spinless binaries in effective-one-body theory based on the post-Minkowskian approximation. The original ‘plus’ and ‘cross’ waveform modes of the gravitational wave generated by coalescing spinless black-hole binaries are extracted from the solution of the null tetrad component of the gravitational perturbed Weyl tensor in the effective spacetime. To enhance the accuracy of the gravitational waveforms, after Damour et al, the waveforms are factored into five components which are the Minkowskian leading factor , the source , the tail effect , the phase factor , and the residual term . In the equal mass ratio case, we find that the reconstructed waveform is closer to the five post-Newtonian result than the original waveform, while the resummation method gives the better results.