The invention is a processing method for instant communication, relating to electric communication technique, and in the instant communication, when a transmitter transmits a message to a receiver R, the message is instantly transmitted to agency receivers if the receiver R is not on-line; these agency receivers as proxy receivers of the receiver R receive the instant message sent to the receiver R; the receiver R arranges the proxy receiving relations of agency receivers by the instant communication system; these agency receivers have a different priority to the proxy reception for the receiver R, and the instant message is sent to high priority ones of these agency receivers; when these agency receivers off-line, the message is stored as an off-line message; the instant message received by the proxy receivers contains a characteristic message, which reflects original belong attribute of the instant message is belonging to the receiver R. The invention assures the realtime and integrity of instant interactive communication.