American culture is unique because it is nurtured， formed and developed under certain conditions， which are characteristically（特性）American. The major factors contributing to the making of this new nation and the forming of a new culture are the hard environment， ethnic diversity（多民族） and plural religion， which is quite different from other nations in the world. What is more， these elements are still influencing the American culture.
1. Rough Environment
The early immigrants who were English Puritans settled down in northeast part of American. The environment there was very rough but they believed the poor land could purify their mind so they chose the place along the coast. From 1607 to 1892， frontiers were pushed further west. The American frontier consisted of the relatively unsettled regions of the United States， usually found in the western part of the country. The frontiersmen looked for a land of rich resources and a land of promise， opportunity and freedom. Actually they looked for a better life. So individualism， self-reliance， and equality of opportunity have perhaps been the values most closely associated with the frontier heritage（遗产） of American.
2. Ethnic Diversity
The population of the United States includes a large variety of ethnic groups coming from many races， nationalities， and religions. People refer to the United States as "melting pot "and the dominant people are British. American is made up of WASP+MM， that is， White， Anglo Saxon， Protestants plus Middle Class and Male. In history， people from different countries in the world rushed to American three times. They brought their own culture to American and later on different cultures were mixed together. Thus the unique American culture is formed， a common cultural life with commonly shared values.
3. Plural religion
The fundamental American belief in individual freedom and the right of individuals to practice their own religion is at the center of religious experience in the United States. The great diversity of ethnic backgrounds has produced religious pluralism； almost all of the religions of the world are now practiced in the United States. Christianity（基督教） is the dominant religion in American and Protestant （新教）is predominate（主导）。 Any individuals are equal before God and they believe they can communicate directly to God so they can share the same idea. Under the protestant， many new ones are formed and different explanations produce different sect of religion. Churches are independent and American religion is no longer religion seculars. The institution permits the practice of religion and the political power is separate form religion. So there are more religions in American than in other countries.
4. Current influence：
Nowadays， we can see the continual influence of the three elements in the current American society. American family is typically parents and their unmarried children. Middle-aged and elderly people generally do not live with their married children. Many Americans live in mobile homes whose homes are built with wheels. They can be moved. The people in American have a very strong desire to start a new life in a new place. Quite a number of people change residences（住所） every year. The average American moves fourteen times in his lifetime. The courage to try something new has been an American characteristic. American democracy means majority rule， but it also means protection of minority rights. There are certain freedom which the United States promises to all its citizens and members of minority group cannot be denied these rights by a vote of the majority. Americans also like to be involved in many challenge activities and sports to show their adventurous spirits. All of these are affected by the heritage of the American history.
From the facts above， we can see American culture is unique which was cultivated， formed and developed by the main three factors， rough environment， ethnic diversity and plural religion and still is affected and determined by them now.