Taking practical saving-energy experience of large-scale baffleless magnesium reduction cell in production process of titanium sponge produced by kroll method in Fushun Aluminium Plant as an example, non-production and production electricity consumption, leakage of electricity and other factors which cause energy waste are discussed. Relations within coarse magnesium D.C consumption in production, current efficiency and working voltage are expounded. And related factors that affect cells working voltage and methods to decrease cells working voltage are also pointed out.