Abstract: The southern margin fault of Yuguang basin is the largest boundary fault of Yuguang basin, which is an active fault zone. The most recent age is the Late Pleistocene-Holocene activity. According to the relevant specifications and standards for measuring the flow deformation across the fault, combined with site environmental conditions, the measuring site of cross-fault flow deformation was selected at the large probe in Holocene active section of fault. The site meets relevant specification and lays a foundation for cross-fault flow deformation measurement.