In order to integrate the evaluation and optimization of transnational power grid projects and to quantify the adjustment of energy interconnection schemes, this paper improved the Min DS (minimum distance to strong efficiency frontier) DEA (data envelopment analysis) model and combined it with gray correlation analysis, which can measure the input-output efficiency and quantify and screen the optimization paths. Taking 10 transnational power grid projects and the Asian Energy Internet Program for case analysis, the study found that the input-output efficiency of the third schemes of China's Xinjiang-Pakistan Project is the highest (2.792). For the Southeastern Tibet-Bang Mumbai Project, there is 1047.368-million-yuan investment cost redundancy. The input-output efficiency of Northeast Asia, Southeast Asia and China in 2050 is lower than that of 2030. On the basis of the Asia Energy Interconnection Program in 2030, North-Central Asia, West Asia and South Asia should increase CO₂ emissions reduction by 0.750,0. 396 and 0. 236 million tons respectively. North-Central Asia, West Asia and South Asia should build more hydro-power, wind energy and solar energy power generation bases respectively in order to achieve this adjustment. This work can provide a tool for the evaluation and optimization of transnational power grid project decision makers and energy interconnection scheme planners.