Soil micromorphology method has been widely used in the study of site soil, which can interpret the information of ancient human activities contained in it. Based on the previous study of the soil at Yangshao Village site, this study collected several cultural layers, ancient soil layers and topsoil layers, and identified ancient human behavior of using fire and cultivating soil by comparing the differences in micromorphology and physiochemical properties. The results show that: 1) Soil matrix affected by fire is mainly red-brown, in which the carbon scraps are scattered, and iron barrier formation is mainly in the form of lumps and fragments. Fine particles are affected by fire, and iron oxides formed by chemical reaction cover them, showing weak interference color characteristics. Most of them are non-separated b-barrier. 2)Artificial traces can be identified in the soil affected by soiling, such as flat holes and scratch traces. There is a clear and flat boundary between different soil barriers, indicating that the compaction of soil. Some fine grains are affected by artificial scraping, and present striped b-barrier junction. In addition to enveloping and bridging, fine-grained and coarse-grained materials also appear filling, which also indicates that the compaction of soil. 3) Invasive bodies such as shells and carbonized plants are found, and the soil microstructure is spongy. In general, the macroscopic characteristics and basic physiochemical properties of the soil confirm the results of micromorphological observation, indicating the fire and farming activities of ancient humans in the area.