Abstract: This research aimed at the windbreak and sand-fixation efficiency of Pennisetum giganteum sand barriers with different stubble height (10 cm and 30 cm)at Liuguaishatou along the riparian zone of the Yellow River in the Ulanbuh Desert.The sand barriers were set by P.giganteum with 1 or 2 m row spacing and 10-15 cm plant distance.The results showed that:① The windbreak and sand-fixation efficiency was closely related to the height and row spacing of P.giganteum sand barriers.For a certain height level,the more the rows and the smaller the plant distance were,the better the windbreak and sand-fixation efficiency would be,but the required materials would be increased;② The sediment discharge in the P.giganteum sand barrier was mainly concentrated within a 15 cm height from the ground,and the capability of preventing wind-blown sand was strong below 5 cm.When the row spacing of sand-barrier was 1 or 2 m,the wind speed was reduced below the sand-removing one after wind blew over 9 or 12 sand barriers; ③ A high efficiency and low cost should be ensured in setting sand barrier.It is considered that the P.giganteum sand barrier with 30 cm height and 2 m row spacing is suitable in arid area.

Key words: Pennisetum giganteum, sand barrier, wind speed, sand flow structure, windbreak efficiency, sediment, Ulanbuh Desert