In Yechangping Molybdenum Mine,shallow-hole shrinkage stoping is adopted,but this mining method has already restricted the development of the mine.In order to meet the requirement of enlarging production scale,the adoption of block caving system to the mine was studied.On the basis of the results of early research and the conditions of rock mass in the mining area,the initial undercut area for continuing block caving was studied with numerical simulation.The result showed that the suitable initial undercut area for the primary molybdenum ore is 2800 square meter,for the oxidized molybdenum ore is 800 square meter.