Abstract: Characteristics of the sink,source and flow of the high-yield hybrid Teyou combinations-Teyouduoxi 1 and Teyou 63 were studied using Indica hybrid Shangyou 63 as control.The results showed that(a) the characteristics of Teyouduoxi 1 were similar to those of Teyou 63;(b) the high-yield hybrid Teyou combination was superior in sink capacity(indicated especially in its bigger panicles) and had more erect leaves in the canopy,higher dry leaf weight per unit area,larger leaf area index,more dried matter accumulation(especially during medium and late growth period),and higher ratio of grains to leaf area;(c) more photosynthate was translated to grains after flowering;and,(d) the flow was efficient from the source to sink.It is concluded that the combined desirable characteristics of the sink,source,and flow contributed to the high yield in Teyou combinations.