In this article,information traffic dynamics in scale-free networks with limited queue resource is investigated firstly. It is found that the network transits from a free flow state to full congestion state with the increase in the packet generation rate. Then,a queue resource allocation model based on node degree is proposed. The core of this model is to make the queue length of node i proportional to kβi (ki being the degree of node i and β being an allocation parameter). Simulations show that the capacity of the scale-free network is maximal when β is about 1.25 for the shortest path algorithm used to transfer information. Furthermore,the optimal value of allocation parameter β is irrelevant to the network size and the amount of queue resource.