Abstract: Residue decline dynamics of fluroxypyr in rice plant,rice and rice hull,paddy soil and water was reported.Fluroxypyr in the samples was extracted with NaOH-methanol,purified with liquid-liquid extraction and detected by capillary gas chromatography with electron capture detector after methyl esterification.The results showed that the average recoveries in paddy plant,soil,water,rice and rice hull ranged from 85.5% to 103.2%,the RSD was from 1.9% to 9.9%,the limit of detection of fluroxypyr standard was 2.0×10-12g,and the limit of quantification in paddy plants,rice,rice hull,soil and water were 0.005,0.02,0.005,0.002 mg/kg and 0.001 mg/L,respectively.The test in Anhui and Guangdong Province in 2007 and 2008 indicated that the half-life of fluroxypyr were from 4.9 d to 6.0 d in plant,while in soil were from 5.5 d to 8.6 d,in water were from 11.0 d to 13.8 d.The final residues of fluroxypyr in rice were lower than Chinese MRL of 0.2 mg/kg.It was suggested that 5% WP of fluroxypyr should be applied to control weeds in rice field with the dosage less than 168.8 a.i.g/ha at period of seedling establishment.