[Objective] To analyze the effect of geomorphic units and land use on the spatial variation of total phosphorus in a small watershed of the Loess Plateau, in order to provide basis for land management. [Methods] In 2017, 267 soil samples were collected in the Wangdonggou watershed. The total phosphorus contents were measured for different geomorphic units and land use types and its spatial distribution was mapped by using ArcGIS 10.2. [Results] The land use patterns and geomorphologic units exhibited an extremely significant effect on the spatial variation of total phosphorus. The content of total phosphorus in different geomorphic units showed as: sorghum> slop> channel. The content of total phosphorus in different land use types showed as: orchards> abandoned orchards> farmland> woodland> wild grassland. [Conclusion] After more than ten years of agricultural intensification, the total phosphorus content has been improved greatly, and the distribution of total phosphorus has been substantially changed by the land use patterns.