Based on precipitation data from the China Meteorological Administration and NCEP-NCAR reanalysis data, the dominant patterns of summer precipitation over Inner Mongolia were investigated on the interannual scale with the EOF and composite analysis methods. This study focused mainly on the typical circulation patterns of the two leading modes as well as features of their related seasonal transition from spring to summer. On the interannual scale, the spatial distributions of summer precipitation over Inner Mongolia were classified into two main types:‘consistent distribution’and‘east-west seesaw distribution’. The consistent distribution type was primarily characterized by a dipole circulation in the mid- and upper-troposphere levels around Lake Baikal, wave-train anomalies in the midlatitudes originating from northern Iran and central Asia, and a circulation pattern with high (low) pressure in the east and low (high) pressure in the west over East Asia. In contrast, the east-west seesaw distribution type featured a wave-train-like pattern propagating from the eastern European Plain, via the eastern Ural Mountains, to eastern Inner Mongolia and Northeast China. Meanwhile, a dipole anomaly pattern with high (low) pressure in the north and low (high) pressure in the south was situated in the mid and high latitudes over East Asia. For both patterns, their positive or negative phase corresponded to an advanced and delayed spring-to-summer seasonal circulation transition over mid- and high-latitude Asia. These results are helpful in deepening our understanding of the interannual-scale variability of anomalous summer precipitation and its typical circulation over Inner Mongolia, thus providing some clues for its prediction.