How to improve the logistics service quality is one of significant problems for logistics alliance which formed by manufacturing enterprise and TPL. Firstly, the decision behavior of manufacturing enterprise and TPL under decentralized decision is analyzed. Then the results under decentralized and centralized decision are compared, and find that results under decentralized decision are inferior to those under centralized. Based on analyzing the cause of that, the coordination strategy is proposed which manufacturing enterprise motivated TPL to reduce the delay rate with reward contract. The conditions for logistics alliance to realize coordination are conducted, and it is revealed that the Pareto improvement of logistics alliance parties can be achieved and the benefit of logistics alliance can be optimum by choosing appropriate reward, Finally, a numerical example is given to illustrate the correlative conclusions.