This paper presents a new assumptions statement generation method for developing TOE security environment section of PP. We surveyed on guides on the assumption statement in CC scheme, and collected and analyzed hundred of assumption statements which are in 26 certified and published real PPs and CC Toolbox/PKB. The CC Toolbox/PKB is included a class of pre-defined assumption statements. From the result of the survey, we developed a new generic assumption statement list, and proposed a assumption derivation method by using the list.