多年来的工作实践及实验证明了重力仪格值随温度变化而改变,而且对观测值的影响极大,以致造成虚假异常。本文对京津唐地区重力资料进行格值改算,再计算唐山地震前,唐山测点自74年4月至76年3月累积重力上升了130微伽,由76年3月到7月短期异常近200微伽。根据异常范围、形态、量值计算震前在莫氏界面断裂处有一个密度异常区。 Years of work experience and experiments have shown that gravimetric cell values ​​change with temperature, and the effects on the observations are so great that they cause false anomalies. In this paper, the gravity data in Beijing-Tianjin-Tangshan area are converted into grid values. Before calculating the Tangshan earthquake, the accumulated gravity of Tangshan measurement point increased by 130 microgas from April 74 to March 76, from March 1976 to July short term Abnormal nearly 200 micro-gamma. According to the range of anomalies, morphology and magnitude, there is an anomalous area of ​​density anomaly at the Mohsian interface before the earthquake.