Loess landforms refer to the complex, diverse and orderly differentiated landform morphological combinations that are formed with unique evolution patterns. Based on analysis of mathematical morphology, this study classifies the loess landforms in Heshui county into loess plateaus, beams and loess hills, and develops corresponding classification indexes for them. Furthermore, according to morphological characteristics and classification indexes of loess morphological units, this study establishes quantitative and visual expression landform evolution models for loess plateaus, beams and loess hills, and predicts the parts of loess plateaus that are going to disappear. Roundness is found to be an important indicator to define the evolution process of the loess landform unit, and it increases as the loess landform evolution proceeds. The boundary between loess plateaus and beams can be identified by the perimeter area ratio and the average slope, while that between loess beams and loess hills can be determined by the boundary adjacency index. The transition from a loess plateau to a loess ridge actually corresponds to the evolution from a residual plateau to a branched loess ridge. It is critical to strengthen grooves and protect loess plateaus, since human beings have to rely and live on these residual loess plateaus.