Program understanding is very important for software changes in maintenance phase. The changes of software's source code might be affecting to other part of code. These situations make the developer spent more time to find the affected line in entire code. In this book, writer is approaching Change Impact Analysis (CIA) method to support the developer's program understanding to find the potential affect or dependency information in source code. A visualization method is be use with CIA as a tools to represent CIA into graphical that able to assist developer find the actual affect in the line of code. The prototype called CIA-V is combining CIA and visualization method based on C++ Object-Oriented language to enhance program understanding ability. CIA-V will assist the developer to understand the program through diagram and save the time to find affected code.