Abstract: The relative researches are carried out with a case of cut slope treatment engineering of expansive soils. It isinvolved that the shoring idea of expansive soils slope, the strength value of expansive soils, the slope stability analysis andits optimizing design, the technics of anchor bar with expanding root and its test study, the protection of sloping surface, andso on. And the anchor bar with expanding root test study indicated in expansive soils area that anchorage forces of theexpanding roots are not obviously different from the those of non_expanding roots when the tests has been done beforeraining, but after raining the non_expanding roots. anchorage force will decrease to a large extent but the expanding roots.decreasing extent is little. Such data indicates that the applications of anchored bars with expanding roots in expansive soilsare successful.