Abstract: Source number estimation is a important technology in spatial spectrum estimation.It is very important to give out a new stable method of source number estimation to fit the real situation.A new improved method for sources number estimation is proposed,which based on ordinary gerschgrion disk criterion and toeplitz algorithm for decorrelates coherent sources.It first reconstruct matrix using toeplitz algorithm,then estimate source number using gerschgorin disk criterion.For that,the new method can make gerschgorin disk criterion be used in estimating sources number of coherent sources in the situation with low SNR.Simulation results demonstrate the validity of the method.