In this paper, the values of annual and seasonal aridity index in the Ebinur Lake Oasis in Xinjiang, China were calculated based on the measured data of monthly precipitation,wind speed, relative humidity and radiation at four meteorological stations in the oasis during the period from1960 to 2013. The linear fitting method,Mann- Kendall mutation test,wavelet analysis and climate sensitivity coefficient test were used. The results are as follows: ① The average aridity index of the Ebinur Lake Oasis was 6. 97 in recent 54 years,and it suggested that the study area could be categorized as an arid region. The aridity index was in a significant decrease trend with an average rate of 0. 49·(10a) ~(- 1) (P < 0. 05) . The average aridity index in summer was as high as 9. 04,but its minimum value in winter was 2. 20 only; ② The annual aridity index in the Ebinur Lake Oasis was sharply decreased in 1985. Seasonally, the sharp decrease of aridity index in summer and winter occurred in 1991 and 1983 respectively,however, there was no mutation of aridity index in spring and autumn; ③ There were 7 - 8 - year and 20 - 21 - year periodic variations of aridity index in the Ebinur Lake Oasis in recent 54 years, the first principal period of aridity index variation was for 9 years,and the second and third periodical changes were for 21 years and 5 years respectively; ④ The aridity index in the Ebinur Lake Oasis was the most sensitive to the change of wind speed, the contribution of wind speed change to the variation of aridity index was the highest,and the aridity index was not sensitive to the change of sunshine duration.