Abstract: The output connection in transitional period was one of the key technical difficulties during the transition from open-pit to underground mining.Taking E'kou Iron Mine as a case，two proposals for the smooth transition were given based on the comprehensive analysis of the mine resources，opencast production status，opencast stripping schedule and underground mining district.One was the underground output production with the aid of open-pit production，and the other was open-pit production with the aid of underground production.These two proposals were applied to the mine to obtain the most realistic programs for smooth transition.

Key words: Transition from open-pit to underground mining, Opencast stripping schedule, Underground mining district, Output connection