It is found that the quality of the same rice variety, which is related with commercial character such as the content of amylose ,white belly and eating quality et al is quite different through analyzing 7 rice varieties including 4 Indica and 3 Japonica rice varieties produced in Jiaxing and Hainan rice breeding bacees.It is clear that the difference is caused by the different temperature condition during the seed development after heading. That is, the higher of the temperature, the lower of the content of the amylase;On the contrary the lower of the temperature, the higher of the content of the amylose in the rice during the seed development after the heading stage. Therefore, when the rice breeding program is conducted at the different place or in the different season , the content of the amylose in rice should be different. Also the quality of rice can be improved through the adjustment of the seeding or heading stage.