Test adequacy analysis usually uses coverage criteria to evaluate test design with respect to specific software characteristics. Conventional adequacy methods have following problems to address test evaluation of large software systems. First, codcbased coverage cannot ensure sufficient verification and validation of software requirements. Secondly,software testing adectuacy needs to take into consideration the contribution of different features. Important features deserve more test effort. hhe paper proposed a model-based approach for test adequacy analysis. An interface model was defined, representing executable software requirements for software components. Coverage of test case design was analyzed at two levels including service and service-compositions. Adequacy was calculated as weighted sum of coverage on various software features. Experiments were exercised to illustrate the proposed approach.