In arid and semi-arid ecosystems, water resources are the key ecological factor restricting the structure and function of the oasis-desert ecotone. The objective of the present study was to determine the effect of environmental factors on the characteristics of stem sap flow and water consumption of Haloxylon ammodendron in the whole growing season. Thermal dissipation sap flow velocity probes (TDPs) and an automatic weather station were used to measure sap flow velocity in trunks of different diameters, and environmental factors such as air temperature (T), relative humidity (RH), solar net radiation (Rn), vapor pressure deficit (VPD), and precipitation (P), respectively, in the Minqin oasis-desert ecotone, Gansu Province, China, from June to November 2014. On clear days, the peak wave area of daily sap flow velocity (SV) of H. ammodendron trunks of different diameters gradually reduced with changing seasons, whereas the phenomenon "broad peak shape" of SV showed as excessive growth from June to August. The SV on cloudy or rainy days was lower than that on sunny days. The SV of different H. ammodendron trunk diameters often fluctuated, furthermore the larger the diameter, the higher the fluctuating during the growing season. However, there was no obvious consistency and relationship between SV and stem diameter. From June to November, the water consumption of H. ammodendron initially decreased, and the highest peak SV was in July. The larger the stem diameter, the water consumption was more higher. Environmental factors correlated positively with SV in different time scales and weather conditions. The weather condition effected the SV correlation of H. ammodendron significantly, where it was higher on sunny than on cloudy and rainy days. The correlation of SV with VPD was the highest with the total weather factors on sunny and rainy days, while the correlation of SV with Rn was the highest on cloudy days. In the study period, the correlation coefficitents between SV and T exceeded 0.842 (P<0.01). Rn was the second-most important influence on SV (R²=0.811, P<0.01), with the third influence factor of VPD (R²=0.769, P<0.01). The correlation of SV with soil moisture in the root area at 0-250 cm level points and 0-100 cm depths was the most significant. Therefore, from the results it could be deduced that H. ammodendron of Minqin is an efficient drought-resistant plant.