Abstract: Analytical method and field residue decline study of 20% hypertonic ethylicin EC in plant,rice,rice hull,paddy water and soil was reported. Samples were extracted with dichloromethane and the extracts were purified on liquid-liquid partition,followed by gas chromatography (GC-ECD) determination. The recovery was from 85.3% ~89.1% for the paddy water,87.0% ~90.3% for the plant,90.3% ~95.4% for the soil with relative stangdard deviation (RSD) of 4.3 % ~6.3 %,2.6 % ~4.9 % and 3.0% ~7.4% respectively. The limit of detection(LOD) was 2.0×10-11 g. The limit of quantification (LOQ) was 0.002 mg/kg for paddy water,0.01 mg/kg for soil and 0.02 mg/kg for plant(rice and rice hull). The results of field residue decline study of 20% hypertonic ethylicin EC in rice in Hunan,Tianjin,Zhejiang,Hubei showed that the half-life of hypertonic ethylicin was 0.3 ~1.1 days in paddy water and 1.4 ~2.1 days in plant,respectively. Non-detectable residue was found in soil,rice and rice hull at harvest time. 0.05 mg/kg was setting for recommended maximum residue limit(MRL) for ethylicin in rice.