Abstract: Taking an open-pit mine in Hegang City as the research background，the mining boundary optimization of the open-pit mine is realized by using Datamine software and NPV program. Block mod⁃ el is created through mining engineering software，technical and economic parameters such as mining cost， beneficiation cost，lean loss rate，stripping ratio and slope parameters such as bench height and slope angle are defined，and L-G graph theory is used to optimize the boundary. According to the change of profit coefficient，NPV program forms a series of open-pit mining boundary schemes. Taking the maximization of NPV (Net Present Value) determined by optimization as the judgment standard，and after manual processing，the final open-pit mining optimal boundary scheme is determined. The results show that Datamine software can effectively improve the working efficiency of determining the optimal boundary of open-pit mining and maximize the economic benefits of mining enterprises.

Key words: open-pit mine, mining boundary, Datamine software, NPV, L-G graph theory