Method for delivering push notification and push notification server for performing the same

The present invention relates to a method for delivering a push notification and a push notification server for performing the method. In the push notification delivery method, by a push notification server, a push notification message is received from a push notification server application. By the push notification server, the push notification message is sent to a push notification client registered in association with the push notification server application. If the push notification message is not sent, the push notification message is stored in a transmission queue within the push notification server and is resent to the push notification client, or an update, expiration or cancellation of the push notification message is processed. A push delivery state of a push notification message, sending of which has finally failed, is changed to a delivery failed state, and failure results are transferred to the push notification server application.