  In this letter, we propose a new routing strategy with a single free
parameter $\alpha$ only based on local information of network topology. In
order to maximize the packets handling capacity of underlying structure that
can be measured by the critical point of continuous phase transition from free
flow to congestion, the optimal value of $\alpha$ is sought out. By
investigating the distributions of queue length on each node in free state, we
give an explanation why the delivering capacity of the network can be enhanced
by choosing the optimal $\alpha$. Furthermore, dynamic properties right after
the critical point are also studied. Interestingly, it is found that although
the system enters the congestion state, it still possesses partial delivering
capability which do not depend on $\alpha$. This phenomenon suggests that the
capacity of the network can be enhanced by increasing the forwarding ability of
small important nodes which bear severe congestion.
