The Bomi region of Tibet is located in the northeast of the Namche Barwa Syntaxis. It is a key area for studying the evolution of eastern Himalayas syntaxis. This study obtained 1200000 Bouguer gravity data in Bomi region for the first time. First, using the wavelet transform multi- scale decomposition method, scratch analysis method and gravity 3D inversion method to divide the tectonic activity unit, we obtained the gravity anomalies of different, faults distribution and density structures. The analysis results show that the overall crust density in the Bomi region changes significantly and is closely related to the fault distribution. At the same time, combined with the regional geological data and our inferred 20 faults in the Bomi area, we found 4 large transverse density uneven zones and deduced the occurrence of Jiali fault zone which runs through the study area. In addition, using the seismic and aftershock activity records in the area, we analyzed the relationship between deep density structure and earthquakes. Finally, according to the transverse variation of fault structure density, seismic activity and gravity anomaly in the study area, it can be seen that the seismic, fault zone and rock density disturbance are closely related to the transverse unevenness, and the earthquakes are mainly located in the overall vertical high- density area of the density difference zone. Based on the above analysis, we discuss the potential influence of deep density structure on large- scale engineering construction in Bomi area.