To allocate the water resources in Lancang-Mekong River Basin, on the basis of the fundamental principles of equitable and reasonable utilization, this study took equity and the status quo into full consideration, paid attention to both efficiency and sustainability, and chose the corresponding indicators to establish hierarchy. Combining subjective and objective factors, analytic hierarchy process and entropy method were integratedly addressed to calculate weights of water allocation. The above weights were weighted further by the combined method based on game theory. Finally, the weights of water allocation were obtained. By comparing the proportion of actual water consumption and the weight of water allocation, the results showed that the water consumption in Vietnam was about twice as its allocated amount, whereas the water consumption in other countries was less than the allocated amount. In order to ensure the rights of equitable and reasonable utilization of water resources for riparian countries, Vietnam should compensate other countries. The conclusion could provide decision support for water resources utilization and water benefit negotiation in the Lancang-Mekong River Basin for China.