An important strand of evidence in support of test validity lies in that the internal structure of a language test concurs with the expected theoretical models of language ability． Using the data from a university-based English proficiency test as an example，this study demonstrated how evidence pertaining to factor structure and factorial invariance can be effectively utilized to support the construct validity of a language test． While presenting important empirical evidence as to the construct validity of this test，this study has provided a different perspective and method of test validation for other examination boards．