Abstract: By studying the differences of rice yield and its components, development of culm and tiller number, development of leaf area and its composition, photosynthetic potential, dry matter accumulation and crop growth rate in super high yield population and high yield population, the population characteristics of super high yield formation of mechanical transplanted japonica hybrid rice were illustrated as follows: 1) The enough number of total spikelets in the population (more than 50 000×104/hm2) was resulted from enough panicle number and large panicle size, meanwhile the seed setting and the 1?000-grain weight should be normal (the seed setting was above 85%; the 1?000-grain weight was about 27 g). 2) The percentage of productive tiller (more than 75%) and the ratio of effective and high effective leaf area (The ratio of effective leaf area was about 95% and the ratio of high effective leaf area was more than 75% at heading stage) were increased on the basis of proper development of culm and tiller number (The expected number of panicle was achieved at critical leaf-age for productive tillers, and the max number of stems and tillers was appropriate, about 1.3 times as much as expected number of panicle ) and the leaf area index (The LAI was 7.8-8.0 in booting stage and then decreased smoothly after heading. At maturity, the LAI remained 3.0) in order to achieve the target productivity at different growth stages. (3) The dry matter weight at maturity stage (more than 20?400 kg/hm2) was increased with focus on increasing the dry matter production and accumulation from jointing to heading (the crop growth rate was about 22.5 g/(m-2·d) and the accumulation of dry matter was more than 9?000 kg/hm2 accounting for 45% of the total weigh of dry matter) and with increasing the dry matter production and accumulation from heading to maturity effectively (the crop growth rate was about 13.5 g/(m-2·d) and the accumulation of dry matter was more than 8 000 kg/hm2 accounting for 45% of the total weigh of dry matter). And the super high yield would be obtained if the rules above are followed in the production of mechanical transplanted japonica hybrid rice.