Abstract:Echinochloa spp., which was a annual weed belonging to Gramineae and had strong adaptibility and wide distribution, was one of the staple noxious weeds in rice, wheat and soybean fields. The author studied the biological characteristics of Echinochloa crusgalli and its controlling methods in rice fields since 1975. It has been shown that the initial temperature for its germination and the optimal temperature for its growth were found to be 12℃, and 30—35℃ respectively. The emergence peak of Echiochloa cursgalli would be predicted by two indices i.e. accumulated temperature biological zero = 10℃ and leaf age. The former was 33.8—49.5℃ when the soil moisture was sufficient and the latter was oneleaf age of Echinoloa crusgalli after puddling. The experiment results also pointed out that the control of Echinochloa crusgalli in rice field should begin with the control in nursery bed and the key to success was to make the effective stage of herbicides coincide with the emergence peak (sensitive stage) of weeds: The chemical control by herbicides such as butachlor, thiobencarb, molinate, oxidizon, dimethametyn (piperophos), pretilachlor and quinclorac combined with agricultural practice such as cleaning up seeds and water management, etc. may result in optional weed control.