Abstract: In order to explore the effective methods of using rice allelopathy, inhibitory effect of allelopathic hybrid rice and new strains on barnyardgrass [Echinochloa crusgalli (L.) Beauv] in the field was compared with‘PI312777’, a strong allelopathic rice of the United States. Two common rice planting patterns including water direct seeding and seedling transplanting were designed as treatment. The inhibition rate before sealing line, the inhibition rate of competition and the inhibition rate of filling stage of allelopathic rice and the average plant height and the dry weight per plant of associated barnyard grass were investigated in this paper. Seedling transplanting treatment had better inhibitory effects on average plant height and dry weight per plant of barnyardgrass compared with direct seeding treatment. The direct seeding treatment had higher inhibition rate of allelopathic rice on barnydgrass and smaller coefficient of variation compared with seedling transplanting treatment. So the direct seeding treatment was a better allelopathic rice planting pattern. The inhibitory effect of allelopathic rice on barnyard grass was influenced by environmental conditions, and the allelopathy effect was relatively stable, while the competition effect varied greatly with the environment. The correlation analysis showed that the grass suppression effects of allelopathic rice did not have obvious influence on the survival of barnyardgrass above ground biomass. Through the enhancement of allelopathic rice allelopathy, the germination of barnyardgrass could be effectively suppressed. The experimental results showed that the allelopathic rice was more suitable for direct planting materials and had a good prospect of application in production.