It is important to build entity modeling which it exists in the outdoor environment with human activities in the nature increasingly. Outdoor entity can be divided into structured, semi-structured and unstructured. This paper uses expanding 2.5D method to model semi-structured entity which it is very representative. The semi-structured entity can be divided into simple standard sample, complex standard sample, simple deformed sample and complex deformed sample in accordance with half-dimensional information gradual deepening complexity. Analyze data structure, build sample modeling. After that, build entity modeling with some operation.