Abstract: Software needs to be maintained and reengineered, as the program techniques. With the study of the concept and models of software recngineering, an method was proposed to recnginecr a massive legacy system combining parallel iteration and software agent technology. This approach was later applied in the reengineering of the FVS system, a FORTRAN program which is more flexible and scalable,and is a good example approach for other reengineering process of similar legacy systems.

Key words: Reengineering, Agent, Parallel iteration