In this paper, the relationship between matric suction and shear strength of the unsaturated remoulded loess soil is examined with experimental approach. It is found that as matric suction increases, the soil shear strength varies nonlinearly. The variation has clear four stages: increasing, decreasing and keeping relatively constant. Particularly, the four stages can be identified based on the correlations between matric suction and shear strength, consistent with those shown on the soil-water characteristic curve. It is also found that shear strength parameter φb of the unsaturated loess soil is not a constant.