The invention provides an ICE (Internet Communications Engine) serving method. Data transmission between an ICE server and an ICE client adopts a UDT (UDP-based Data Transfer Protocol) data transmission method to transmit a UDT protocol package, and can adopt a UDP (User Datagram Protocol) data transmission method to transmit a stun protocol package. The ICE server carries out conversion of the UDT protocol package and the stun protocol package by a UDT agent unit. The invention further provides the ICE server and the ICE client, which correspond to the method. According to the invention, data transmission between the ICE server and the client adopts the UDT data transmission method, and the UDT data transmission method adopts a congestion control and data reliability control mechanism in the data transmitting process, and thus, reliability of data and data traffic optimization can be guaranteed to the greatest extent. The ICE server simultaneously receives the UDT protocol package and the stun protocol package, and has good compatibility.