The　trust　of　an　entity　is　based　on　its　behavior＇s　trust　in　trusted　computing　technology,　and　software＇s　trust　can　be　measured　dynamically　by　its　behavior　when　it　is　executing.　However,　conducting　dynamic　measurement　is　a　big　challenge.　Defining　and　building　software＇s　behavior　is　the　basic　work　of　measuring　software　trust.　A　behavior-based　dynamic　measurement　model　for　an　execution　program　is　provided,　which　applies　the　method　of　describing　program　behavior　by　control　flow　graph　to　dynamic　trust　measurement.　The　model　first　measures　the　program　before　it　is　loaded,　then　generates　the　expected　behavior　model　of　the　program　according　to　static　analysis.　Then,　the　model　monitors　the　program＇s　execution　in　real　time　by　verifying　the　flow　branches　of　the　program　with　the　expected　behavior　model.　Finally,　the　paper　analyzes　the　security　of　this　model　and　indicates　that　this　model　is　able　to　protect　against　some　code-injection　attacks　which　can＇t　be　handled　by　the　traditional　static　measurement　method.