Abstract: The slot allocation is one of the key technologies in IEEE802.16 mesh networks.This paper proposes a diffserv-based slot allocation mechanism (DSSA).At first,we adjust the start time of scheduling window,in order to optimize the number of the scheduled tasks.Then,we assign different search scopes with scheduling window,in accordance with the type of tasks,with an objective to achieve slot reservation that satisfies the requirement in delay of real-time tasks.Finally,DSSA records the arrival rates of tasks periodically,which is used to predict the number of arriving tasks.We can adjust the number of reserved slots according to the predicted value.Our simulation results demonstrate that,DSSA can efficiently enhance the scheduling efficiency of the real-time tasks,while satisfying the requirement in slot allocation of non-real-time tasks.