[Objective] The sap flow dynamics of Sabina vulgaris and the influencing factors was studied in order to provide theoretical support for the protection of sandy land vegetation.[Methods] The dominant species of S. vulgaris on the Ordos Plateau, which was the typical natural sandy land vegetation in Inner Mongolia, was taken as a case. The sap flow dynamic of S. vulgaris was monitored by thermal dissipation probe technology. Its relationships with climatic factors were analyzed by correlation and regression analyses.[Results] The sap flow dynamics of S. vulgaris was a single-peak curve on sunny days, and a double-peak curve during drought; however, it was a single-or double-peak curve on rainy days. The daily maximal value of sap flow of S. vulgaris was 2.30-23.38 g/(cm²·h) on sunny days. There was a 1-4 days time lag in the response of the sap flow of S. vulgaris to rain. The sap flow was significantly positively correlated with photosynthetically active radiation, vapor pressure deficit, air temperature, and wind speed, but it was significantly negatively correlated with relative humidity and precipitation in the growing season.[Conclusion] The sap flow of S. vulgaris on the Ordos Plateau varied with weather. Solar irradiation and water were the main influencing factors for the sap flow of S. vulgaris. S. vulgaris shrub land should be protected to prevent vegetation degradation caused by excessive water consumption.