Dry and water shortage are the main restrict factor for grain output increasment of non-irrigated slope field in Yuanmou dry and hot valley. In order to utilize soil through-flow moisture fully and reduce seasonal drought, the underg round plastic sheet wall experiment in the non-irrigated slope field in Yuanmou county was carried out in 1999. The result indicates, that the output of the non-irrigated slope field with underground plastic sheet wall is increased by 7. 1%～ 20. 2% compared with the cont rast area.