Abstract: Contingent valuation method(CVM)is widely used in environmental impact assessment, but it is also critical. Major criticisms of which revolve mainly around its validity and reliability. There are many factors impacting CVM results bias. In which, “scope effect” is one of the main reason. The major objective of this paper is to summarize scope effect relating this theory issues and to investigate whether “scope effect” existing in this phenomenon. The result reveals that “scope effect” was not a universal matter for CVM and not deficient in something itself.