High evolvability is the remarkable character of component-based software (CBS), and brings great pressure to the testing activity. Recently, aspectoriented programming has been proposed as an effective technique for modulating separate concerns, and facilitating the maintenance and evolution of software system. In this paper, we use this technique to improve component?s testability so as to facilitate component?s unit testing and regression testing of CBS as follows: Self-checking aspect is embedded to check the invariants which the component should obey, and tracing aspect is introduced to collect precondition of method execution in component so as to help regression testers to pick out precise subset of test suit. In addition, two examples are used to demonstrate the feasibility and effectiveness of our presented methods.