Component-based software (CBS) is built through the ways of composition and integration, this development style is quite favorable for modification or upgrade of system. However, making sure that the modified system still works is a challenge. In order to facilitate the maintenance activities and their optimum configuration, it is necessary to measure the changes. This paper mainly discusses the case of component modification, including the single component change and the changes of multi-components, and presents the algorithms for measuring the change impacts in CBS for each situation. Finally, the on-going research plan is addressed.