TCP/IP protocol only provides services of ‘Best Effort’ level, lacking of the support of QoS. An adaptive QoS negotiation mechanism is proposed in this paper, which relies on RSVP (resource reservation protocol), carries out QoS mapping, starts the adaptability functions and the resource management functions while QoS accepting, and makes negotiate between both sides until a group of QoS values have been achieved. The basic steps of implementation by GQoS, as well as the important data structures and functions are introduced. The experimental results show that by applying the approach the QoS parameters can be adjusted adaptively when the network resources changed.