It is an effective approach to obtain high-power laser beam output while maintaining good beam quality by combining multiple fiber lasers. The far-field intensity distribution for coherent combining and incoherent combining with conformal focusing transimitting is numerically calculated, and the effect of phase error, beam jitter, and fill factor is studied in detail to make a contrastive study of coherent and incoherent combining. It is shown that more energy will be encircled in the main-lobe by coherent combining. However, the far-field intensity distribution by coherent combining will be seriously affected by the beam jitter and fill factor of the laser array. And the tolerance on phase error has been improved by using conformal focusing transmitting scheme. For phase error with root-mean-square (RMS) value of π/3, more than 90% energy of the totally coherent combining counterpart will be contained in the target area with radius of 5.6 cm.