We have systematically analyzed the relationship between ML ≥ 3.5 earthquakes in Changning window and moderate-strong earthquakes in Sichuan and its adjacent area recorded by Sichuan Regional Seismic Network since Jul.,1970.The result shows that ML ≥3.5 earthquakes in Changning window can be considered as the middle-term prediction indicator whether or not M≥5.5 or M≥6 earthquakes occurred in Sichuan and its adjacent area,especially for M≥6 earthquakes in Sichuan area.