The purpose of the study is to analyze the characteristics of American expansionism in terms of historical pespectives. Some writers tend to regard the u.s. expansionism in history as "only a phenomenon of great aberration" ; however, such interpretation often give rise to serious debate with many scholars indicating inherited imperial-minded policy since colonial age. Those arguments can be summarized as follow : firstly, one can easily find ' geopolitical determinism' and ' centralism' suggested by such ideologists as Charles Vevier or William Gilpin etc. As can be seen in this thesis those arguments were closely connected with the overseas expansionism in near future. Secondly, the expansionism-minded in congress never agreed with the concept of natural right of men ; accordingly, they were strenuously in pursuit of making imperialistic policy in light of national interest. Those arguments were justified with such ideologies as 'subjective determinism', 'pychological determinism' and 'dotrine of inevitability' etc. Conclusively such expansionism refelecting a national ideology seems to appear in the entire history of America on the whole.