Abstract: Desert Steppe in Inner Mongolia grassland is the most drought grassland ecosystem which transit to the desert, Under a dry climate, the ecological environment is fragile, the impact of climate change on the fragile Desert Steppe ecosystem is more prominent. In this paper, based on the international tundra plan （ITEX） simulated warming effects on plants, using 20cm, 30cm, 40cm, 50cm, 60cm of five highly Open-top chamber （OTC）, to study the dynamic response on the microclimate of Desert Steppe The results showed that, The impact of warming control using OTC to the above-ground air temperature of 20cm was greater than the impact on soil temperature, and the soil temperature of underground 5cm was greater than soil temperature of underground 10cm; Daily maximum temperature of OTC was higher than control processing, but daily minimum temperature was lower than the control processing; OTC of the same base area, the higher of the height, the higher of its daily maximum temperature, and the lower of its daily minimum temperature, that to say, along with the height increase, the daily range of temperature in OTC increase, and sunny day was obvious than cloudy day.