The electric and hydraulic control system of hydraulic support is the critical part for the mechanized working face to work productively and efficiently. Its energy transfer and conversion were realized by the hydraulic fluid containing high content of water as transmission medium. Nowadays we mainly use the simply treated mine water in the hydraulic fluid, and the treated mine water still contains various ions of suspension. Those impurities can damage some sensitive parts of the control system and result in the paralysis of the whole system in the worst case. Therefore, the quality control of the mine water used in the electric and hydraulic control system is very crucial. This paper is to examine the mine water quality index in conjunction with case study, discuss the negative effects of mine water on the electric and hydraulic control system, and propose scientific solutions.