Abstract: Under the background of climate warming, the authors studied the change characteristics of 0℃ boundary temperature in Tibet, in order to rationally develop agricultural climate resources. Based on the daily air temperature data of 38 meteorological stations from 1981 to 2014, by using the linear trend method, the M-K method and anomaly, several elements were analyzed, including the beginning day, terminal day, duration and accumulated temperature of the daily temperature above 0℃ stably. The results showed that the beginning day was in advanced with a rate of 3.1 d/10 a, the ending day was delayed with a rate of 1.9 d/10 a, the duration was increased 5.0 days per decade, and the accumulated temperature of the daily temperature above 0℃ stably had an increasing trend, which increased 83.2℃ per decade in Tibet, and the change was more obvious in lower altitude. It was also found that the inter-decadal variation trend of the critical temperature ≥0℃ presented the characteristics of earlier beginning day, delayed terminal day, prolonged duration and increased accumulated temperature in most part of Tibet. In Tibet, the climate mutation point of the first day and the accumulated temperature occurred in the early 21^st century, the mutation time of the terminal day was in the late 1980s and that of the duration was in the mid-late 1990s.