Based on the characteristics of lighting system, the design of city lighting system was proposed which combined PLC with the MCGS. The system adopted the time control of street lamp, and the brightness detection device was supplemented. The opening and closing of the lamp control by PLC could not only ensure the shortage of time control method due to the change of weather, but also saved energy. The introduction of configuration technology could realize realtime automatic monitoring of the whole system. At last, the whole simulation and debugging of the control system was realized by computer simulation technology. Experiments proved that the system ran smoothly and had reliable performance, friendly manmachine interface, high level of automation, good market prospect and application value.