A series of nearly N-S-trending active tectonic belts are found in Tibet. The earthquakes there mostly belong to shallow-focus ones, and are characterized by high frequency, high intensity and short recurrence intervals. The epicentres are mainly located near the boundary faults along the active tectonic belts. They are most concentrated, with small earthquake magnitudes, at the turning or intersecting parts of the boundary faults, and are less concentrated, bat with big earthquake magnitudes, in other parts of the boundary faults. The mechanic properties of the seismic fracture belts are generally related to their strike: the NW-trending ones are of dextral strike-slip nature and the NE-trending ones are of sinistral strike-slip nature, while the nearly N-S-trending ones exhibit the nature of tensional normal faults. In the region the earthquakecontrolling structures are considered to be the active tectonic belts, while the seismogenetic structures are the boundary faults in the active tectonic belts.