Abstract: In the optimization of the open-pit boundary，the variation of the optimization parameters has a great influence on the ultimate pit limits.The surface restriction is one of the most important parameters for optimization.The effect of surface restriction on boundary optimization was analyzed to determine the rationality of the ultimate pit limits and achieve the maximum benefits.Taking Shuguang Gold-copper Mine in Hunchun as a case，the mine is divided into different regions according to the final slope division and the slope optimization result.According to the geological exploration data and actual production data of the open pit，the common Kriging method is used to estimate the grade value and the grade model is built.Then，the open-pit mine boundary with surface restrictions and no surface restrictions is optimized based on L-G graph theory.The optimization results showed that more than 28.67 million tons of ores are additionally explored in the mine with no surface restrictions boundary，compared with that of the surface restrictions，and the effect of surface restrictions is not obvious when the price is low.The surface restriction has the greatest influence on the Ⅳ zone.If the Ⅳ area is to be mined，such costs as mineral rights，forest rights and other costs are less than 160 million yuan.

Key words: Boundary optimization, L-G graph theory, Kriging, Surface restrictions