The Kokyar shelterbelt in the peri-urban area of Aksu in Xinjiang Wei Autonomous Region is a model project for large scale artificial afforestation in arid regions with extreme water shortage.Authors selected Populus bolleana at three different stand ages(6

15 and 22 year stand age

respectively) as a research object.Taking bare sand a control，the windbreak efficiency at the heights of 0.5 and 2.0 m and the soil improvement effects are analyzed.Results show that Populus bolleana shelterbelt had a very distinguished windbreak effect.Leeward windbreak efficiencies of different aged Populus bolleana at the height of 0.5 m were showed as the order of 22 year stand age>15 year stand age>6 year stand age

while at the height of 2.0 m

windbreak efficiencies were presented as the order of:15 year stand age>22 year stand age>6 year stand age.The comprehensive windbreak efficiencies of 15 year and 22 year stand age Populus bolleana were very close

and both were better than 6 year stand age.Soil bulk density decreased significantly

especiallv within the 10 cm of topsoil.Soil organic matter and nitrogen content increased with the increasing stand age and available nitrogen

potassium content increased first and then decreased

while available phosphorus content deceased first and then increased.