Abstract: A complete understanding of the transitional zone from oasis to desert was achieved，which had been long-term disputed，based on the abundent accumulation from continuous observation．Cele oasis is chosed as an example to analysis the ecotone from oasis to desert．As a typical type of transitional zone from oasis to desert，the Transitional Zone from Oasis to Sandy Desert can be defined as the desert zone from the edge of oasis(border of artificial protection system or natural sparse shrubs ) to fixed or semi-fixed sandy ground with the vegatation cover between 20%～25% on the outer edge between oasis and mobile desert. The inner boundary of the transitional zone is the artificial protection system on the periphery of oasis，including shelterbelt defending wind and sand or natural sparse shrubbery. The formation of transitional zone is due to the gradient difference of environment factors such as water and temperature that exist from oasis to the outer desert，leading to the transitional feature of the integrated landscape that showed by vegetation，soil and geomorphology，etc. Its composition and structure pattern is sparse shrubs (or shelterbelt system on the edge)-gentle relief ground with bushes and herbs where sand settled-relief ground with bush-herb cones and high relief ground with bush-herb cones in the direction from oasis to desert. The transitional zone is an important region to be retained and protected for native flora and fauna，a buffer zone where energy and material can be transported and exchanged between oasis and desert，and a natural ecological barrier for oasis. It has a protective function on topography，soil and vegetation，and plays an important role in carbon sequestration．

Key words: Transitional Zone from Oasis to Sandy Desert, Structural Feature, Function and Properties