In order to understand effects of strong wind-sand flow blowing on growth properties of Pinus sylvestris var.mongolica seedlings and its photosynthetic responses,we conducted a field wind-sand flow blowing experiment with 18 m·s^-1 wind speed (wind-sand flow intensity 173 g·cm^-1·min^-1) and a time gradient of 10 min,20 min and 30 min in the Spring,2013 in the Horqin Sand Land of Inner Mongolia.The results showed that:(1)With increase of wind-sand blowing time,amount of plant height growth slowed down,amount of stem diameter growth accelerated,number of fallen leaves increased.The amount of plant height growth decreased by 52.63%,amount of stem diameter growth increased by 233.30%,and fallen leaves index increased by 466.70%,respectively,in the 30 min treatments compared to the CK.(2)Wind-sand flow blowing did not changed the diurnal variation pattern of photosynthetic rate,transpiration rate,stomatal conductance and intercellular CO₂,but resulted in decrease of the daily maximum photosynthetic capacity and increase of the maximum daily transpiration rate,which decreased by 22.69% and increased by 11.89% in 30 min treatments compared to the CK,respectively.(3)With the increase of wind blowing time,the leaf temperature,RWC,daily mean photosynthetic rate and WUE tended to decline,which decreased by 0.60%,4.37%,28.57% and 31.58%,respectively,in 30 min treatments compared to the CK.The daily mean transpiration rate,stomatal conductance and intercellular CO₂ concentration tended to increase,which increased by 6.25%,6.67% and 12.60%,respectively,in 30 min treatments compared to the CK.The results suggested that the photosynthesis was inhibited,transpiration water consumption increased,and water use efficiency decreased while P.sylvestris var.mongolica seedlings were stressed by continuous sand flow blowing.The decrease of photosynthetic rate resulted mainly from decrease of leaf temperature and leaf water content,and the increase of transpiration rate was mainly due to increase of stomatal conductance.In order to adapt to the continuous blowing sand flow stress,P.sylvestris var.mongolica seedlings reducded the height growth rate,speeded up growth rate of stem diameter.