Abstract: Before the two earthquakes, there are long-term trend ground fluid anomalies lasted for longer than half year. In the short term, there appeared some remarkable microscopic and macroscopic anomalies of underground fluid before two earthquakes. At the same time, the quantity and trends of the anomalies undulated, even appeared "relative calm" just before the events. The anomalies happened some migration and evolution in the space, displayed from the dispersion to the concentration toward the future epicenter. The appearance of the macroscopic anomalies, which are mainly composed of underground fluid, can be considered as a short-tern signal of a strong earthquake, but it is closely related to the regional seismotectonics, the distribution distance may be far and the lasting time may be rather long.

Key words: Earthquake, Underground fluid, Anomaly change, Sichuan-Yunnan area