ThepaperdiscussesquantitativelytheinfluenceoftheYutianMS7.4earthquakeofMarch21,2008andWuqiaMS6.9earthquakeofOctober5,2008onregionalseismicityinXinjiang,andexplainsprimarilythepossiblereasonofearthquakeactivityfeatureinXinjiangaftertheYutianMS7.4earthquakebyanalyzingthestaticCoulombfailurestresschangeproducedbytheYutianMS7.4earthquakeandWuqiaMS6.9earthquake,andtheseismicityfeatureofMS≥3earthquakesinthepositiveCoulombstresschangeregionofKashi-Wuqiajointregion,thecentralsegmentofTianshanMountainandKalpinblock.TheresultshowsthattheYutianMS7.4earthquakeofMarch21,2008,mayencouragetheWuqiaMS6.9earthquakeofOctober5,2008,andtheYutianMS7.4earthquakeandWuqiaMS6.9earthquakemaychangetheseismicitystateinthecentralsegmentofTianshanMountain,KalpinblockandKashi-Wuqiajointregion,andencouragethesubsequentMS≥3earthquakes.
