A method provides a call-connected party's information to a terminal in a private exchange network. The method displays the call-connected party's information in a private exchange network, and provides accurate information of a call originator to a terminal of a call receiver. The private exchange system is connected to a CTI (Computer Telephony Integration) server having a database including a phone number and various information corresponding to the phone number, and includes at least one terminal being a slave terminal for receiving/displaying information of the database. A method for providing a call-connected party's information in a private network using the private exchange system includes: a) if there is an information retrieval request for a certain phone number in the private exchange system, generating an information retrieval request message having the requested phone number in the private exchange system, and allowing the private exchange system to transmit the information retrieval request message to the CTI server; b) upon receiving the information retrieval request message from the private exchange system, checking whether there is a database matched with the phone number contained in the information retrieval request message in the CTI server, generating a database checking result message, and transmitting the database checking result message to the private exchange system; and c) upon receiving information matched with the phone number from the CTI server, allowing the private exchange system to transmit the information to a corresponding terminal.