Abstract: Based on the eleventh generation of international geomagnetic reference field (IGRF) model and the NGDC-EMM-720-V3 model of crustal magnetic field,this paper aims to analyze the vertical component of the main magnetic field,the non dipole field,secular variation,long-term acceleration and crustal magnetic anomaly above the surface and the surface of different height distribution in Mongolia and its adjacent area,and to discuss the relationship between the crustal magnetic anomalies and geological structure.The results show that spatial changes of the main magnetic field components in Mongolia and adjacent areas is small,crustal magnetic shows slug,ribbon,arc shaped and the distribution is relatively complex.The anomaly center of Ulam Uhde and Ulan Bator area are relatively stable.Mountain Hangai and Mountain Altai present negative magnetic anomaly,the anomaly distribution is consistent with the mountain tectonic trends.The transition area of positive and negative magnetic anomaly is basically consistent with the boundary of the mountain and basin.