The periodic characteristics of normal and abnormal signals in gravity observation data from Tai an station are analyzed systematically.The relationship among the high-frequency abnormal signals and typhoon,strong earthquake and atmospheric pressure is studied.The results show that the signal period are about 2~4 minutes for normal cases and 2-3 minutes for abnormal cases,the amplitude of signals for abnormal cases are about 5 times than for normal cases.High-frequency abnormal signals are mainly caused by the typhoon which originated on western Pacific Ocean and go to China mainland or near regions, with percentage of 90%, and the signals are positively correlated with the velocity in center of typhoon. The abnormal signals would disappear with typhoon ended. Some abnormal signals are related with trong earthquake, taking number of 17.24% of earthquakes. But the signals have no relation with atmospheric pressure.