Abstract: In order to better understand the isostasy of the crust beneath Ordos block and its surrounding regions, we take into account laterally variation of crustal density in the calculation of isostaty anomalies. Firstly, obtained by the inversion for regional gravity anomaly and Moho depth when calculating the isostasy anomaly; Secondly, we compared theoretical Moho depth and real one which is inverted from the receiver function so as to get the crustal isostasy in the studied regions. Finally, we discussed the relationship between the isostatic gravity anomaly and distribution of earthquakes in this region. The results indicate that the negative isostatic anomaly mainly corresponds to basins, and positive anomaly to mountainous regions, therefore the interior of Ordos block is basically in isostatic state. Moreover, the most major earthquakes mainly occurred on the isostatic anomaly gradient belt in the studied region.