To ascertain economic setting location and remaining period of blocked-out coal reserves in surface mine, with the basic principle of the surface mining and statistical method, we analyzed the characteristics of developing change and its influence on setting location and remaining period of blocked-out coal reserves. Based on the principle of optimal economy benefit, the relationship between setting location of blocked-out coal reserves and internal dumping transportation distance in multi-coal seam surface mine was studied, and an optimization model of setting location of blocked-out coal reserves was built. We also studied the relationship between remaining period of blocked-out coal reserves and stripping cost, transportation cost, time value of money, and built an optimization model of remaining period of blocked-out coal reserves. Taking a surface mine in east of Inner Mongolia as an example, we ascertained the economic remaining period of blocked-out coal reserves in this surface mine should be 6.5 months, and blocked-out coal reserves should be set in 1^# coal seam. The results show that the optimization model can guide production, decrease stripping cost and increase economic benefit of surface mines.