In this paper, we identified repeating earthquake doubles in Huoshan Seismic Window in Anhui province using waveform cross-correlation method, and searched out Repeating Earthquake Sequences (RES) from these earthquake doubles. We picked a good RES which are composed of 8 repeating earthquakes occurred in the years from 2009, chose one event as reference object, and calculated the differential variation of coda Qol of other 7 repeating earthquakes with the reference one using Moving Window Spectral Amplitude Ratio method,which was first proposed by Richard (1996). The result indicated that the RES coda e1 exhibited an obvious decrease from 2009 and returned to normal level in 2010. In other words, the RES coda Qc increased from 2009 with an amplitude about 11%-21%. However, there was no moderate or strong earthquake during 2009 in and around Huoshan Seismic Window, but the seismicity of small earthquakes enhanced in 2009 instead. Based on geodynamical knowledge and the previous studies on the correlation between the great earthquake activity in West China and strong earthquake activity in North China, we consider that the variation of RES coda Qc1 during 2009 could not be attributed to the developing process of a large earthquake, but probably have been influenced by some external factors such as the western continental material eastward movement and the stress transferring, and hence giving rise to the increase of coda Qc.