Abstract: The uncertaint completion time of the mining area is caused by the driving speed of coal mine roadway.And the driving speed is affected by the geological conditions and management of technology and equipment,and so on. In order to cause the entire mining area construction period schedule is variable.The possibility construction period of mining area is expected to combine CPM and probability distribution of the mathematical analysis method in the 31 mining area of Qinan Coal Mine production technology condition. Which is make the schedule to be completed on schedule. The method can also provide reference for similar engineering construction is expected.