Glacier change was investigated by using Landsat TM5 and glacier inventory from 1970 to 2009 in the Kaidu River Basin (KRB) in the southern slope and in the Manas River Basin (MRB) in the northern slope of the Tianshan Mountains. Then, combining with records from weather stations, the differences of glaciers and glacier change between the two basins are analyzed. It is found that there were 2 522 glaciers with glacierized area of 1 356.1 km~2 in the study regions in 2009. And in the period of 1970-2009, glaciers had shrunk 494.33 km~2 in area, accounting for 26.8% (0.8%·a~(-1)); ice storage had decreased 32.73 km~3, accounting for 27.9% (0.8%·a~(-1)). Shrinking ratio of ice storage was slightly greater than that of glacierized area decreasing. In addition, both the area shrinkage and the storage decrease from 2000 to 2009 (1.3%·a~(-1)) were larger than those from 1970 to 2000 (0.6%·a~(-1)). The area shrinking ratios from 1970 to 2000 and from 2000 to 2009 were 0.5% and 1.4% in MRB, and 0.9% and 1.1% in KRB, respectively. Thus, the glacier shrinking acceleration was greater in MRB than that in KRB from 2000 to 2009. Based on climatic records, glacier retreat was mainly controlled by air temperature rising, and the differences in precipitation and temperature variations were the key factors to glaciers retreating in MRB slower than that in KRB.