The invention discloses an electric controlling device for side form placing equipment of a precast member by adopting automatic path optimization, which is applied to the field of side form placement of precast concrete production lines. The electric controlling device comprises a disconnector QF, a switching power supply PS1, three motor control circuits and four servo driver control circuits, wherein an encoder of a servo motor is connected to a servo control unit CU320-2DP through a Drive-Cliq cable, forms closed-loop position feedback in the servo control unit CU320-2DP and finishes servo positioning control; finally, a command is respectively transmitted to the servo control unit CU320-2DP, contactors KM(1-3) and electromagnetic directional valves YV(1-10) for controlling through a Profibus-DP, intermediate relays KA(1-10) and the outputs of the intermediate relays KA(1-10), and further the process of path optimization and placement is realized. According to the electric controlling device disclosed by the invention, a path optimization control command is converted into a digital command signal which can be recognized by a servo system in a single-chip microcomputer controller, the digital command signal is transmitted to a servo driver execution unit through a DP (Data Processing) network bus, and the system performs control according to an automatic path optimization program.