The abnormal characters of seismic active state and rate for small-medium earthquakes before mederate-strong earthquakes in different regions of Tianshan seismic belt, in Xinjiang region, with the seismicity statistical parameter valueβn are analyzed quantatively, and the middle-term prediction index ofβn values before mederate-strong earthquake are refined. The result shows that whenβn value is satis- fied with abnormal index in different region, there may occur Ms5 - 6 earthquake within about one year in the northern Tianshan mountain and the east part of southern Tianshan mountain ; Ms5. 5 - 7.0 earth- quake within about one year in the Bachu--Atushi region and Kashi--Wuqia region. In the aspect of earthquake occurring time, mederate-strong earthquakes in Urumqi, Wusu--Shihezi and KashimWuqia region occur nearly afterβn value anomaly ends ; some mederate-strong earthquakes in BaichenmKuche and Bachu-Atushi occur whenβn value is in the state of anomaly. Small-medium earthquakes in different regions about one year before mederate-strong earthquake have regional character： small-medium earthquake activity increases in Urumqi region; increases and quiescent in the Wusu--Shihezi and Kashi--Wuqia region;quiescent in the Bachu--Atushi region; but are not obvious in the east of southern Tianshan and Akesu--Bachu region.