The invention relates to a self-discovery client, communication terminal equipment and an automatic discovery method thereof, and belongs to the technical field of computer networks. According to theautomatic discovery method for the communication terminal equipment, the self-discovery client actively sends a request message in an Ethernet link layer message communication mode based on an MAC address; communication terminal equipment performs message monitoring, the response message is returned to the self-discovery client after the request message is monitored, so that the communication terminal equipment does not actively upload the message any more, the whole process does not depend on an IP, a TCP or UDP port does not need to be additionally opened, the possibility of suffering from network attack is reduced, and the security of the communication terminal equipment after accessing an operation network is improved.