A remote monitoring system and method for electricity demand of a fused magnesium furnace group. The system has a data acquisition device, a local PC, a cloud server and a remote PC. The data acquisition device has a voltage transformer, a current transformer, an active power transducer, a first slave computer, a plurality of multi-purpose electronic measuring instruments and a second slave computer. The method includes acquiring smelting current and smelting power of each fused magnesium furnace and electricity demand of the furnace group, controlling the switch off/on of each fused magnesium furnace according to the smelting current and the smelting power of each fused magnesium furnace and the electricity demand of the furnace group, sending basic monitoring data to the local PC, and achieving data exchange between the local PC and the remote PC through the Zookeeper technology.