The invention discloses a signal source number estimation method improved through combination of a fourth-order cumulant and gerschgorin circles and aims to improve source number estimation performance under the colored noise environment when a source number is close to an array element number of an array. The method comprises steps that firstly, array elements of the array are utilized to receive signals to construct a fourth-order cumulant matrix, and redundancy elimination is carried out; secondly, the fourth-order cumulant matrix after redundancy elimination is taken as a gerschgorin circle method to receive a covariance matrix of the information, after unitary transformation, the circle center information of the gerschgorin circles is utilized to carry out compression and descending sort of radiuses of the gerschgorin circles, and source number estimation is accomplished lastly through gerschgorin circle criteria. The method is advantaged in that the method is applied to the technical field of source number estimation in spatial spectrum researches.