To understand the effects of sustained wind-sand flow on the photosynthesis and transpiration rates of Pinus sylvestris var. mongolica saplings, a field wind-sand flow experiment with a gradient of wind speed treatments (0 [CK], 6, 9, 12, 15, 18 m/s) was conducted in the spring of 2013 in the Horqin Sand Land of Inner Mongolia. The results showed that:(1) wind-sand flow over 9 m/s can significantly change daily photosynthesis rate patterns, (2) wind-sand flow over 12 m/s can significantly change daily patterns of stomatal conductance, (3) wind-sand flow of 15 m/s and 18 m/s can significantly change the daily WUE pattern, and (4) different strengths of wind-sand flows had a lesser effect on daily transpiration rates and intercellular CO₂ concentrations compared to photosynthesis rate. Compared to the CK, the daily maximum and average photosynthetic rates increased by 12.35% and 13.8%, and 18.33% and 38.9%, at the 6 m/s and 12 m/s treatments, respectively, and decreased by 17.9% and 18.9% at the 18 m/s treatments, respectively. The daily maximum and average transpiration rates increased by 51.9% and 16.9%, and 58.6% and 53.0%, at the 6 m/s and 15 m/s treatments, respectively, and decreased by 22.5% and 18.5% at the 18 m/s treatment, respectively. The daily maximum and average intercellular CO₂ concentrations did not significantly differ with the 6-12 m/s treatments, as compared to those in the CK, but increased by 86.9% and 16.5%, and 44.5%, 3.28% with the 15 m/s and 18 m/s treatments, respectively. Compared to the CK, the daily maximum and average stomatal conductance increased by 14.1%,26.6%, and 27.6%,45.2%, at the 6 m/s and 15 m/s treatments, respectively, and decreased by 11.95% and 13.70% at the 18 m/s treatment, respectively. The daily average WUE increased by 7.33%, 1.93%, 18.15%, 3.09% at 6, 9, 12, and 18 m/s respectively, and decreased by 13.51% at 15 m/s.