In this paper,the correlativity of seismic activity in Guangxi with those in the master seismic zones (belts) of China has been studied by using correlative analysis method of grey system theory.The results show that the degree of association of seismic activity is the largest between the Guangxi seismic zone and the southeast coastal seismic belt (r=0.86). Based on the results,the correlativity of seismic activity in the Guangxi seismic zone with that in the southeast coastal seismic belt has been discussed further.It is found out that the change of seismic activity has been synchronous in the Guangxi seismic zone and in the southeast coastal seismic belt since 1900,and that the correspondence relation of moderately strong earthquakes in the zone with those in the belt is very obvious.