The invention provides a voltage sag evaluation process based on a matrix factor. The process includes the steps that (S1) a voltage sag evaluation object is determined, and voltage sag data of a common coupling node of the voltage sag evaluation object are measured; (S2) the voltage sag data are analyzed and sorted, and a voltage sag sensitivity matrix and a voltage sag frequency matrix are built; (S3) a voltage interruption frequency matrix on the common coupling node is computed, and voltage interruption times are obtained through the voltage interruption frequency matrix. By means of the process, actual conditions of equipment when voltage sag occurs during operation of a system can be truly reflected, and the process is suitable for computer processing.