Traditional VoIP architecture cann’t be brought to MANET environment because of the characteristics of MANET

such as self-organizable

centraless

etc. The alteration of traditional VoIP architecture is obligatory for the sake of be seasoned with MANET environment. This paper proposes a scheme of design VoIP system on MANET using SIP. The scheme relies on extension SIP UA and the introduction of dusting in SIP. We have also analyse the workign mechanism of the main functions. The VoIP system who adopt the architecture can either fit MANET or communicate with current SIP system seamlessly. We also have an outlook of the future work at the end of the paper.