Abstract: The method of quantitative determination of indoxacarb residue on soybean was established by GC/ECD.The residual dissipation dynamics of indoxacarb was studied and the safe application technology was demonstrated.The results showed that the method of quantitative determination was simple,accurate and available.The average recovery was ranged from 86.8% to 90.1%,RSD was ranged from 3.85% to 5.24%,LOD was 0.01 ng and LOQ was 0.005 mg/kg. The original sediment content of indoxacarb was different while different pesticide treatment was applicated.The original sediment sprayed with 96.43 g/hm2 of the effective composition was more than sprayed with 48.21 g/hm2.When indoxacarb was sprayed twice at 7 days intervals ,the original sediment content was more than sprayed only once.Field residue decline study of indoxacarb in soybean was followed first order kinetic equation. In early season the decline coefficient (︱k︱) was 0.174 75±0.000 15,T1/2 was 4.0 d,T0.99 was 26.3 ~26.4 d,and in late season︱k︱was 0.108 35±0.004 95,T1/2 was 6.1 ~6.7 d,T0.99 was 40.6 ~45.5 d.In the demonstration field,after 25 d and 30 d of the last spraying with conventional dosage (i.e. 67.50 g/hm2) in the late season of 2006,the residue was 0.065 ~0.102 mg/kg for spraying once and was 0.032 ~0.081 mg/kg for spraying twice at 7 d intervals respectively.After 15 d of the second spraying,the residue for spraying twice at 7 d intervals was 0.097 ~0.132 mg/kg in the early season of 2007.The residue was less than 0.2 mg/kg which was accorded with the demands of MRL in Japan.