An Internet Protocol telephony exchange system and a call control method thereof. The exchange system integrates an IP terminal and a legacy terminal in a single exchange system, controls a call of the IP terminal in the same manner as an extension subscriber, and contains at least one IP terminal connected to the IP network. The IP terminal contains a user interface for generating user information or converting received user interface information into information of a user-identifiable state, and performs a VoIP function in compliance with one or more of a H.323, a MGCP and an SIP protocol procedure. The IP network is connected to an IP driver and an IP-PBX (Internet Protocol-Private Branch Exchange). The IP driver controls an IP end point at which the IP terminals are positioned, upon receiving IP terminal connection information and call control information based on H.323/MGCP/SIP protocol procedure.