Drought is one of the major natural disasters in north China. Monitoring and analyzing the change of drought indices can shed some light on the assessment and early warning analysis of the droughts, as well as the formulation of disaster prevention and mitigation schemes. Here, the gridded precipitation dataset (0.5°×0.5°) of a semi-arid steppe region in Inner Mongolian Plateau from 1962 to 2017 was used to calculate the standardized precipitation index (SPI) at different time scales (annual and seasonal), then the spatiotemporal variations of drought during this period was studied based on the analysis of the frequency of drought events, drought frequency and station frequency ratio. The result indicate that in recent years, the severity of drought in the study area has worsened, and the south-central regions were the high occurrence areas for different types of drought events. In addition, light droughts occurred mostly in the autumn, which were primarily located in the central and southern regions. Whereas the extreme drought events mostly occurred in the summer, and the high frequency area was located in the west of the study area. Large scale light droughts occurred in all seasons in the 1990s, the domainal moderate drought and the domainal extreme drought occurred in 2001 and 2010 in summer, respectively.