Abstract: In order to fully solve the problem of end slope stability in soft rock open pit coal mine, this paper takes the south slope of Baorixile Open-pit Coal Mine as engineering background, analyzes the improving slope stability effect of horizontal mining internal dumping and tracking pressure and proposes a reasonable mining plan by the methods of geological surveys, laboratory tests, numerical simulations and so on. The results show that the south slope can satisfy the requirements of slope safety reserve when the length of the dumping line reaches 140 m. At the same time, the end slope supporting effect of stope and dumping site is obvious when the inner dumping tracking distance does not exceed 35 m. Therefore, it is recommended that the length of the south slope dumping line should be more than 140 m, and the inner row tracking distance should not exceed 35 m.