The invention relates to an electric control system for opening and closing of a sludge discharging door with an MJS construction method. The electric control system comprises a motor reducing gear, a worm, a worm wheel, a screw rod and the sludge discharging door, wherein the motor reducing gear is connected with the screw rod in a transmitting mode through the worm and the worm wheel, and the screw rod is connected with the sludge discharging door through a screw thread; guide rails are arranged on the two sides of the sludge discharging door, and the motor reducing gear is connected with a control circuit leading to the ground through a reserved wire hole; the motor reducing gear is controlled by the control circuit to drive the screw rod to rotate forwards and rotate backwards through the worm and the worm wheel, and therefore the sludge discharging door moves up and down to be opened and closed. The electric control system is suitable for controlling the opening and closing of the sludge discharging door with the MJS construction method. Compared with the original oil pressure control system, the electric control system greatly reduces key links, is not easy to fail and the advantages of simpleness and convenience, low cost and easiness in maintenance. In the material selection, the components such as the motor reducing gear, the worm wheel, the worm, etc. are matured products on the market, and the quality assurance is strong.