Abstract: China is the top rice producer in the world, heavy metals especially cadmium in rice (Oryza.sativa L.) has become a hot-spot topic in recent years, thus it is one of the most important work for the government to avoid“cadmium polluted rice”in agricultural production. The accumulation of cadmium in four rice varieties during filling to ripening stages under three field conditions was studied. The results showed that cadmium in rice grains had significant differences between the 16th days (the 1st sampling time) and the 36th days (the 6th sampling time) after flowering, but there was no significant difference between the 20th day (the 2nd sampling time) and the other five sampling times (i.e the 16th, 24th, 28th, 32nd, 36th days after flowering). The results showed that cadmium concentration determined on the 20th days after flowering was similar to those determined afterwards. This early determination could be used to predict cadmium content, and hence used in early warning for safe management.