In the semi-arid and soil erosion region of western Liaoning, we should develop forests to conserve water and soil above all so as to prevent soil erosion and recover soil fertility. In contrast to the pure forest the Chinese pine mixed forest had obvious superiority in improving physical and chemical as well as antierosion properties of the soils. The mixed forest of Chinese pine and broadleaf trees (including shrubs) could increase soil wetness by 10-30% and humus content by 7-76.4% and decrease the volume weight of the soil by 10%.In addition, the mixed forest of Chinese pine and broadleaf trees could raise the water-stable soil aggregate by 22.2-124.4% and reduce the soil erosion rate by 6.6-26.3%. In this area the suitable species to be used as the mixed trees should include Acer trumcatum, Quercus m ongolica, Caraaana microphylla etc.