Beginning with the origin of the concept of the validity,this paper divided the development of the validity theory into four phrases:the phrase of the origin of the concept of the validity,the phrase regarding the criterion-related validity and the content validity as the central role,the phrase regarding the construct validity as the central role,and the phrase of unitary concept of validity.

This study,developing and piloting a questionnaire as an instrument, using relevant statistical procedures, investigated the extent to which the essay in TEM8 (TEM8E) is a valid test in terms of theory-based validity.

The paper introduces the theoretical validity of oral testing,the testee s language communicative competence in real context,and discusses the ways to realize the theory-based validity in oral testing from three perspectives: the test tasks and the test formats,the testee s performance,and the scoring reliability.

In light of the theories of "theory-based validity" in language testing and "cognitive writing process", this article theoretically explores the writing ability oriented in "theory-based validity" in English language writing tests and develops a theoretical model for "theory-based validity" in the assessment of English writing.