The invention discloses a VoIP analog gateway for achieving conversation under fault condition and an internal exchange method. The VoIP analog gateway may be switched between a logon operation state and an internal exchange operation state. In the logon operation state, the VoIP analog gateway periodically logs on call control equipment, and enters the internal exchange operation state if the logon operation fails. In the internal exchange operation state, the analog gateway processes a call request according to information pre-configured in a data storage device in the logon operation state, and respectively processes the requests according to conditions. By using the invention, the VoIP analog gateway can locally communicate with each other to achieve call communication when the call control equipment fails, when the IP network fails, or when the VoIP gateway fails to connect the call control equipment.