Credibility is the key factor for system simulation. The HLA simulation system based on BOM can promote the reusability and interoperability on the simulation model level. To insure the credibility of this simulation system, it is very necessary to study VV&A in modeling and simulation of all the life cycle. Firstly, the FEDEP (Federation Development and Execution Process) model of HLA simulation system based on BOM is introduced, and the VV&A process is put forward briefly. Then the research of V&V for user model, simulation model component and federate are made. Finally the approach is applied in the anti-ship missile's penetration federation. The result shows that the VV&A process is feasible, which can ensure the credibility of the simulation system.