The invention provides method for publishing, querying, subscribing to information by a SIP terminal in a VoIP network system, a SIP terminal, a SIP application server, a SIP information center and the VoIP network system. Wherein the VoIP network system is deployed with SIP information center for storing and providing at least the information. The method for publishing information by a SIP terminal in a VoIP network system comprises: creating a publishing request with the information to be published embedded in at the SIP terminal; sending the publishing request from the SIP terminal to the SIP information center via the SIP application server; recording the information in the SIP information center's database; and notifying the new information update to the subscribed SIP terminals.