The conventional time-domain back-projection (BP) imaging method typically suffers from performance degradation when the echo signals are interfered by noise. In this letter, a virtual-echo projection imaging method is proposed for noise suppression, including the suppression of the additive white Gaussian noise and the irrelevant colored noise. First, the proposed method calculates a number of coarse imaging maps by projecting the realistic echoes on the virtual echoes. Second, the fine imaging maps are calculated by accumulating all the coarse imaging maps coherently. The performance of the proposed method is numerically investigated in comparison to that of the traditional BP method. The results indicate that the proposed method outperforms the conventional BP method in suppressing both the additive white Gaussian noise and the colored noise.