Abstract: Along with the increasing frequency of natural and man-made disasters all over the world, the demand for relief supplies has been accelerating in the last decade. When disasters strike a certain area, non-for-profit organizations (NGOs) will purchase relief supplies from suppliers and/or collect donations from donators, then deliver relief supplies to disaster-affected areas to help victims. In practice, however, the relief logistics suffers a serious delay, along with an enormous social and economic loss.The unreasonablestructure of the relief supply is a major reason. Therefore, it's necessary to study the relief supply network and explore its structure optimization. Towards this end, a complex relief supply network is deconstructed into 8 linear relief supply chains based on the purchase-warehousing-transportation decision-making process. This deconstruction method has three features:(i) completeness, the universal set of all substructures is the general structure; (ii) independence, every substructure is of independence and doesn't include or affect other substructures; and (iii) integrity, every substructure includes complete process and decisions of a relief effort. Afterwards, a structure optimization model is developed to obtain the optimal combination of relief supply chains to minimize the social loss of a relief operation. The purpose of the model is to obtain the minimum-cost supply chains combination without deteriorating the relief performance or the maximum-performance supply chains combination without increasing the monetary cost. Moreover, the proposed model is verified by the real data acquired from 5.30 YingJiang Earthquake in 2014. Different structure optimization results are compared and analyzed by adjusting parameters or changing external conditions. The comparison and analysis suggest that the types of relief supplies and affected areas have significant effect on the optimal network structure, while the demand quantity of relief supplies has little effect on the network structure. This study clarifies the constitution and process of a relief supply network, which lays the foundation for further improvement. The proposed structure optimization model not only can be used to construct a relief supply network in time for emergency situation, but also provide directional guidance for the construction of relief reserve system.

Key words: relief supply network, deconstruction, structure optimization, humanitarian operations management