Provided is a method for chatting messages by topic based on subscription channel reference in a server. The method may include: receiving a message transmission request from a first user terminal corresponding to a first user to a second user terminal corresponding to a second user; extracting a subscription channel to be referred to by parsing the received message; reading a corresponding client handler with reference to a subscription channel stored in a subscription channel storage; and transmitting a message to the first and second user terminals through the read client handler.