Abstract: In order to master the electric power quality status and features of the mine electric power supply system jointly operated with the mine electrified railwa y system, to improve the mine electric power supply safety and to protect the affectivity of the mine contral plan, in combination with the actual electric power supply co nditions of a 110 kV mine electric power network, the electric power quality measuring and test technology, the stable regression harmonic source position technology, t he PsCad negative sequence current simulation technology and other method were applied to analyze the electric power quality status of the mine electric network, thre e phase unbalanced cause and the harmonic current upward features under the influences of the electrified railway to provide the scientific basis to the selection and C ontrol of the later electric power quality control technology.