Abstract:：As a apart of open-pit mining,limit optimization is very important,which can provide reference of open-pit mining design,at the same time, it can maximize the comprehensive utilization of the resources and maximize the benefits of the enterprise,making the long-term strategic planning of the enterprise come ture.In this paper,with a open pit in Tibet ,the operation of dynamic open-pit limit optimization process of Whittle software will be introduced in detail, through the analysis of a series of optimization results, combined with the principle of maximum net present value (NVP), selecting the optimal open-pit,then design the final open pit.