Effects of different sowing rate on yield and dry matter production for mechanical precise-quantity direct seeded rice were studied using japonica rice Yongyou 8 and Wuyunjing 19 as materials. The results showed that the yield of 1.5~2.2 kg/667 m2 sowing rate （Yongyou 8） and 2.2~3.0 kg/667 m2 sowing rate（Wuyunjing 19） were highest than other treats. The population of stems and tillers of which achieved the expected number punctually at the critical leaf-age for productive tillers, and reached the peak with an appropriate value, ultimately arrived at a higher ratio of productive tillers to total tillers. Their maximal LAI appeared at the booting stage and the values were appropriate. The dry matter accumulation of both two models were remarkably higher than others from heading to maturity. The numbers of dry matter accumulation of 1.5~2.2 kg/667 m2 sowing rate （Yongyou 8） and 2.2~3.0 kg/667 m2 sowing rate （Wuyunjing 19） were highest in maturity.