Abstract: In the process of open-pit mining，there always exists problems like shifting the equipment and the haulage lines.Frequent shifting work will slow down the schedule and reduce the efficiency.However，without shifting，the longer transport distance will affect the production plan and reduce the economic benefits.Therefore，determining a reasonable shift spacing plays a significant role in mine production.With Heidaigou Surface Mine as the research object，according to the actual open-pit mine production and mining theory basis，the factors of affecting shift spacing to the middle coal channel was analyzed in detail.The mathematical model of shift spacing for coal channel was founded，through mathematical modeling method.What′s more，based on the shifting feature of groups of crushing stations，the shifting spacing model for the shift compensation was established to determine the occasion to start shifting.The shift optimization model reveals the influence of shift spacing to the mine economic benefit.The research has a certain guiding significance to the shifting of surface mine，which can improve the economic benefit of surface mine.

Key words: Open-pit mine, Coal channel, Semi-continuous process, Shift spacing