Abstract: The Zhalantun area of the eastern part of Inner Mongolia is located at the northern section of Greater Khingan seismic belt, and it has complicated geological structure with relatively dynamic moderate-strong earthquakes in history and modern times. Seismic activities in this district is selected as the research object. Based on the completeness analysis of seismic sequence in the district, least square method is used to conduct time scanning calculation of b values, and maximum likelihood method is used to conduct space scanning calculation of b values. b value during the scanning time is the mean b value of research zone in every scanning window, so its amplitude of variation is not quite great, with variation range within 0.78～1.13, and of error range within 0.04～0.065. Space scanning results indicate that the space distribution range of b values basically stays within 0.4～1.8, and error range within 0.045～0.085. Low b value zone is in the north central section of the Arun River breakage, with b value within 0.5～0.7, which indicates that the earth crust medium of this zone is under the state of high horizontal stress accumulation and it maybe the dangerous zone where moderate-strong earthquake might occur in the future.

Key words: b value, Space and time scanning, Zhalantun area, Eastern part of Inner Mongolia