Tetrapion(2,2,3,3-tetrafluoropropionate sodium) has commonly been used for reed(Phragmites communis Trin.) control in uncultivated areas, especially in Japan. As an attempt to establish the screening system for selective herbicide controlling reed, tetrapion was tested as a standard herbicide to various weeds and crops including rice in a greenhouse. Symptoms of yellowing, twisting, stunting, and necrosis were observed in the herbicide-treated plants. The herbicide caused a severe damage on all crops examined, except cotton. Both direct seeded and transplanted rice were also sensitive to the herbicide. Its herbicidal activity was generally higher on grass weeds than on broadleaf weeds. It had a higher herbicidal activity with preemergence treatment than with postemergence treatment. In addition, field and greenhouse experiments were conducted to examine the effect of the herbicide on reed control. Its effect varied with the soil type of the treated field and the growth stage of reed. A relatively high dosage of the herbicide was required to control reed. It had an almost same effect on fairygrass(Miscanthus sinensis Anderss) as on reed. However, reed grown in a greenhouse was effectively controlled by the herbicide, having more effect with preemergence treatment than with postemergence treatment as observed in other plants treated with the herbicide. In conclusion, tetrapion has a great potential as a standard herbicide during the herbicide screening for selective reed control.