Abstract: The descriptive linguistics school is a main linguistics school in America during the period from thirties to fifties of the twentieth century.It is known as linguistics school for its attaching importance to the description of linguistics materials and forms of linguistics structure.Franz Boas,Eward Sapir,L.Bloomfield and Z.S.Harris hnve contributed greatly to linguistics of America,but because of the limit of conditions and circumstance,the school also has its own evident defects.