Abstract: Wideband distributed coherent aperture radar can achieve more subtle information when detecting targets, due to its high range resolution and high angle resolution. And accurate coherent parameters are keys to wideband full coherence. When detecting long-range target, single radar always fail because of its relatively low SNR. Therefore, accurately estimating the coherent parameters in order to achieve coherent synthesize under low SNR is core in long-range detection of distributed coherent aperture radar. In this paper, the wideband dechirped echo model of high velocity complex target is built firstly. The mathematical expression of coherent parameters is presented. Then a novel coherent parameters estimation method based on MUSIC in wideband distributed coherent aperture radar is proposed. The number of the target’s scattering centers, the corresponding poles and complex amplitudes of the scattering centers can be estimated, resulting in the noiseless rebuild signal. Based on this clean signal, coherent parameters are estimated. Finally, simulations are carried out to illustrate the performance of proposed methods under low SNR.