In this paper, according to the basic rule of the equitable and reasonable utilization of water resources in international rivers, the normal approaches of resolving the conflicts over water and the basic models of water allocation are introduced. The tendency and the problems of water utilization among the riparian states in Lancang-Mekong River are discussed. The extent of cooperation and the conditions of the management institution of the river basin are analyzed. In the present situation, it is considered that the basin-wide allocation model of water resources is the best one in Lancang-Mekong River.