Based on the continuous observation data at the 90 meteorological sites in Xinjiang, a selfcalibrating Palmer drought severity index (PDSI) is firstly used to investigate the annual and seasonal variation of drought and wet conditions in the region during 1961－2003. During the concerned period, Xinjiang is characterized by normal climate condition, and both annual and seasonal mean climates are prone to become wetter as a whole. Qualitative analysis reveals that the recorded surface warming tends to induce drought, whereas increased precipitation is favorable for wetness. Under the SRES A2 emission scenario for atmospheric greenhouse gasses and aerosols, projected surface warming tends to induce drought, whereas increased precipitation tends to induce wetness in the 2090s. Taking into account the above two factors together, the PDSI indicates that drought and wet conditions in Xinjiang alter to some extent in the 2090s.