Abstract：A N-S trending profile has been set along the 106°E longitude and high-precision gravity data of this area was obtained for the first time. After a series of pretreatments and corrections, gravity anomalies of the profile are obtained. Analyses indicate that free-air anomaly of this profile is closely related to terrain. Bouguer gravity anomaly changes gently along the profile and relatively fast changes only occur in areas near the Gobi-Altai belt (GAB) and Haraa belt (HRB). The rapid gravity anomaly change may indicate a rapid change of deep structure, and such gravity anomaly change is not found around the Mongol-Okhotsk orogenic belt. The isostatic gravity anomaly of the profile is mainly negative, equilibrium has not been reached for most areas. The correlation between earthquake activity and isostatic anomaly of the profile is similar to research results of the northern North-South seismic belt.