The existing direction-of-arrival (DOA) estimation algorithms of coherent signals using single snapshot limited the types of incident signals or lost array aperture. To address this problem, the novel algorithm was proposed utilizing the crosscorrelation information of receiving single snapshot data to constitute equivalent covariance matrix. Combined with MUSIC or ESPRIT algorithms, the DOA of coherent signals could be estimated. The proposed algorithm was not dependent upon the types of incident signals and avoided the loss of array aperture. The performance of the algorithm is better than those of the existing algorithms under scenarios of low SNR by randomly superimposing a few snapshots. Computer simulation results confirm the effectiveness of the proposed algorithm.