Since the establishment of the Tenth "Five-year Plan" digital seismic network,the South China Speed Model has been used in Inner Mongolia Digital Seismic Network. The researches of large seismic velocity and seismic cataloguing in many years show that the speed model in South China does not conform to the characteristics of geological structure in Inner Mongolia. The 2015 speed model of Inner Mongolia used in 2016 could not fully meet the needs of seismic positioning in various regions of Inner Mongolia. In this paper,all the seismic phase data of M_L ≥ 3.0 recorded from 2009 to 2016 were used to invert the suitable models of regional crustal velocity structure for the western,eastern and central regions of Inner Mongolia by the way of velocity fitting and travel time reducing. At the same time,the models of western velocity,eastern velocity and middle velocity were compared and analyzed. The position error of the crustal velocity model of each subarea is smaller than before,and the advantages of its reliability and stability are obvious.