In the paper, according to the revealed major indicators on river health assessment and of transboundary water allocation in the preliminary studies, after the correlations among them were analyzed, the key indicators of transboundary water allocation and of healthy riverwere finally confirmed, as: mean annual runoff, maximum water intake, and minimum maintained water volume. Based on 38 international treaties related to water allocation in 1864-2002 adopting the 3 key indicators, some key hydrological data of the 28 rivers covered by the treaties from various publications were looked up, the values of the 3 key indicators were standardized and calculated, and the thresholds and the regional characteristics of them were analyzed. The results were as follows: (1) Among the 3 key indicators, "minimum maintained water volume" was most widely adopted, and "maximum water intake" was the one with the lowest adoption. (2) From the adoption of mean annual runoff, for the frontier rivers, the basic scheme of water allocation was equal allocation, and the threshold was 50%; for the tributary, which was totally within one country, the threshold was 100%; for transboundary rivers, there were more schemes with a different allocation, and more ones with a greater share for an upstream country. (3) As for the indicator of “minimum maintained water volume”, its adoption showed the extending tendencies from the developed regions to the developing ones, and from maintaining water supply for downstream countries to keeping ecological water demand. When it was used for maintaining water supply, at the river scale, the average thresholds were 41.7% on transboundary rivers and 50% on frontier ones, respectively, which were obviously affected by riparian countries’ strength, while at the reach scale, the average threshold was 36.1% on transboundary rivers. When it was used for keeping water flow in watercourse, the average value of the thresholds was 14.7%, with an increasing tendency.