Abstract: Wang No. 11 well showed oil-evuption anomalies before the 1976 Tangshan earthquake and its strong aftershocks. According to statistics, the earthquake-response probability of oil eruption of the well to the earthquakes with M≥4 occurred in Tangshan old seismic zone was 75%;after the well-hole re-jetting in 1984, pressure of the sealed well was observed. The earthquake-response probability of its pressure variation anomalies to the earthpuakes with M≥4.5 occurred in Tangshan old seismic zone reached 75%. The observed pressure showed hour-value sudden changes, which has a quite important reference value for earthquake prediction.