In order to understand effects of sand burial on height growth of Pinus sylvestris var.mongolica saplings and its physiological responses,we investigated the changes in plant height,membrane permeability,osmotic adjustment substances contents,protective enzyme activities of P.sylvestris var.mongolica saplings in different sand burial depths in the Horqin Sand Land of Inner Mongolia in 2013.The results showed that:(1)The sapling could grow normally,plant height and bud length were significant higher when buried depth was lower than 2 cm above saplings height compared to no-buried CK,with a maximum increased magnitude at sand burial depths of 50% of sapling height.When burial depth was higher than 2 cm above sapling height,although the plant height and bud length increased than buried before,they were lower than the CK,and all the buried saplings were not speared out of the earth and then all died.(2)Soluble sugar content was significant lower,POD activity and soluble protein and proline contents were higher at all the burial treatments than that at the CK.(3)With increase of burial depth,RWC(relative water content) tended to increase,but the differences were not significant at all the burial treatments compared to the CK;MDA and soluble sugar contents tended significant decrease,and soluble protein and proline contents and SOD and POD activities increased firstly and decreased later,and membrane permeability had not significant differences at most the burial treatments than that at the CK.(4)The results from correlation analysis showed the correlation between membrane permeability and MDA content was almost zero;proline content had a significant positive correlation with soluble protein content,and soluble sugar content was significantly negatively correlated with proline content.The results suggested that when sand burial depth was lower than 2 cm above sapling height could promote height growth of the saplings,and did not result in membrane lipid peroxidation,also did not cause cell membrane damage.When the sapling subjected sand burial stress,SOD,POD,soluble protein and proline played an important role in preventing the membrane lipid peroxidation and maintaining cell turgor pressure,respectively,while soluble sugar did not play a role in osmotic adjustment.