Arid region is sensitive to changes in precipitation, while global warming and El Niño-Southern Oscillation strongly influence worldwide hydrometeorological processes. Temporal and spatial changes of characteristics including precipitation, annual mean temperature and area in China's arid region were analyzed, using daily precipitation and temperature data from 117 meteorological stations of 1961-2016. The results show that: (1) During the past 56 years, the precipitation in the arid region have shown an increasing trend. The annual and quarterly precipitation all exist a cycle of about 4 years. (2) The area of the arid region has been on a downward trend since 1968, decreased significantly after 1998. There are two main cycles of 13 years and 5 years in the area of arid region. During the study period, the center of the arid region’s precipitation moved 0.14° to the north and 0.77° to the east. (3) During the past 56 years, increasing of the arid region’s temperature has been more obvious than the average temperature increasing in China. In 1990, the annual average temperature in arid region changed from a decreasing trend to an increasing trend and there is a negative correlation between the area of arid region and the annual mean temperature, which is significant at the 0.01 level. (4) The degree of precipitation response to ENSO in the eastern part of the arid region is more obvious than that in the western part. El Niño events extended the size of China's arid region and increased the average precipitation in the arid region. The precipitation of the east increased more than the west. And La Niña events significantly reduced the area of the arid region, with more precipitation than the average in the eastern part and less precipitation in the western part. The impact of ENSO is one of the reasons for the arid region's center of precipitation shifting eastward.