The key technology of organic rice culture is controlling the growth of weeds in rice field effectively.Experiment was carried out for control weeds in rice field by deep-water management,rice bran application,coverage of rice field surface with organic matters such as rice straw and chaff.The results showed that deep-water control can effectively control the development of Japanese millet in rice field.The efficiency of weed-control by rice bran application can reach 85 percent of that by herbicide.The coverage of rice field surface with rice straw and chaff can also control the growth of weeds in rice field to varying degree so that to lower the cost of rice bran application.