An information exchange method and system, a server and an instant messaging client are provided. The method may include: when receiving a chat session request message sent by a first instant messaging client in an intercom group, receiving, by a server, chat session audio information transmitted by the first instant messaging client; and when receiving a chat session stop message sent by the first instant messaging client, distributing, by the server, the chat session audio information to instant messaging clients, except the first instant messaging client, in the intercom group for real-time playing. The instant messaging client implements an intercom talk function based on a network, thereby saving the purchase cost and improving the confidentiality and stability of information exchange.