A method for call processing and link test in a Voice over Internet Protocol (VoIP) Gateway and system thereof. When a Gateway with Gatekeeper is operated in manual Registration/Admission/Status (RAS) mode, the link test is selectively performed depending on the status of the Gatekeeper according to an access code, whereby traffic of the Gatekeeper can be dispersed. In addition, when the Gateway with Gatekeeper is operated in manual RAS mode, depending on the status (i.e. enable or disable) of the Gatekeeper according to the access code, VoIP call processing or call routing service is divided into public VoIP service for charging a VoIP call and local VoIP service with free of charge. In case there is no routable Gateway during the VoIP call service, the call is detoured to Public Switched Telephone Network (PSTN) network for processing. As a result, service reliability of VoIP network is greatly improved.