Abstract: Based on the relativities of the time and the space,the schemes of transition of mining from open-pit to underground were compartmentalized to project of transition with boundary pillar,transition in full-area and in subarea.The advantages and the shortages of the three schemes were expatiated simply.The stable transition project was brought forward with the case study of transition from open-pit to underground mining in Mengjia Iron Mine.Also,the technical measures of this project were discussed from the allocation of production of opencast,the design and construction of underground mine aspects.The authors are looking forward to giving certain guidance on mines being on the point of transition from open-pit to underground mining in our country.