Abstract: Open-pit optimization is an important part of open pit design,which directly affects the scale,the investment,service life and other aspects of the mine.Using the Surpac software as a platform and value block model as the core,the open-pit optimization of one Copper-molybdenum Mine is made.By analyzing the main factors affecting the pit,a multi-program comparison studies are conducted based on the price and recovery of Molybdenum which are the main variable.A final pit is finally recommended by comparison and the preliminary design is completed,and some key indicators are calculated such as mine(rock) quantity,stripping ratio and metal quantity.The study provides a reasonable technical solutions and investment decisions for the resource exploitation.Meanwhile,the open-pit optimization can be a reference by other similar large low-grade polymetal deposits.