On the basis of data of 30 observation wells for the dynamic of groundwater and oil from 1973 to 1978, evolving process of anomalies of groundwater and oil dynamic before and after the Tangshan 7.8 earthquake is analyzed and studied. The results show the evolving process can be divided into four stages. The anomalies arise first in near epicentral area and then anomalous areas spread outward, showing several concentration point of anomaly. In middle-short stage, anomalous areas clearly contract and migrate from outer-ring to epicentral area. In the imminent stage, an anomalous concentration area with high value is formed in the epicentral area.