Tworocksampleswithdifferentstructuresandmaterialsweredeformedunderabiaxialloadingsystem,andmulti-pointstrainmeasurementswereperformedforeachsample.ThedistributionofstrainanomaliesduringthedeformationandtheinstabilityprocesswereanalyzedbyusingCvvalueputforwardbyWANGXiao-qingandCHENXue-zhong,etal,aparametertodescribetheheterogeneousdistributionofearthquakeprecursors,soastoexaminethemethodofCvvalueandtoexploreitsphysicalmeaningexperimentally.TheresultshowsthatthechangeofCvvalueiscorrelatedtothechangeofdeformationcharacteristicsandisaneffectiveparametertodescribetheheterogeneityofprecursordistribution.Cvvalueincreasesfirstlyandthendecreasesbeforetheinstability,andtheinstabilityoccurswhenCvvaluedecreasestothelevelbeforeincreasing.ThisindicatesthatCvvaluemaybeausefulparameterforearthquakeprediction.