The economical threshold of Brandt's Vole (Lasiopodomys brandtii) was analyzed in the typical steppe in Inner Mongolia. Results showed that the economical threshold of vole fluctuated from 1995 to 2012. From 1995 to 2005, the economical threshold is 36.4, 48.8, 45.2, 39.6, 51.2, 51.7, 48.6, 47.2, 45.4, 40.8, and 40.1 voles per hectare, and from 2010 to 2012, the economical threshold is 41.8, 39.8, 38.7 voles per hectare respectively. The economical threshold of voles is mainly affected by two factors: the annual income to herd a sheep and the character of the population dynamic of voles in current year. The relationship of the annual income of sheep-herding and the economical threshold is inverse proportion. Based on the results from 2010 to 2012, the economical threshold of Brandt's Vole is about 40 individuals per hectare in recent years.