erence in respect of national benefit exception and ivestment risk assumption. Ingeneralcircumstance ahosts tateshouldprotectbenefitsofinvestors accordingtoBIT proveisions，butitcanalsotaketherelevantmeasures tomaintainnationalbenefits as soonas thespecial situations listedinNPMclauseappear.Itis probablethatNPMis easytobeabusedbecauseofthe abstractobjectives inNPMclause. Inordertodeterminetheconditions forapplicationof NPM，itis necessarytoconstruethekeywords inNPMandconfirmrelevantreviewstandards onthem.As forthe problems ofwhetherChinashouldacceptAmericanstyleNPMclauseandhowtorestrictabuseofsuch aclause thisar ti clewill makeanaly sisof howtobalancebenefits ofthehoststateandinvestorsunder NPM in respects of NPM's function，framework，clause construction，and review standards，and induce preliminary conclusions with combination to the consideration of protect against risk and security of Chinese oversea investment.