Currently， power grid companies at home and abroad both lack experience in large-scale application of DC deicer. Problems such as low efficiency of deicing and insufficient optimal configuration of deicer have limited the role of DC deicer in standing against wide area ice disasters. Based on a summary of the experience gained in applying DC deicer of China Southern power grid， an analysis is made of the priority and dispatch optimizing methods for transmission line deicing， together with a proposal for the minimum-load-guarantee operation scheme for fighting extremely serious ice disaster. Suggestions are made for perfecting the principle of optimal allocation for DC deicer and a prevention strategy for wide area ice disaster of power grid based on DC deicer is put forward.