This study was carried out to develop a simultaneous analysis of multiple pesticides in feed. The method was tested rice straw silage for analysis of 171 selected pesticides and metabolites. The samples were extracted using citrate buffer, and purified with primary secondary amine (PSA) and C18. Acidic pesticides were purified without PSA, and LC-MS/MS and GC-MS/MS were used for determination of pesticides. Acetate buffer was used for pymetrozine instead of citrate buffer. Recoveries at three spiked levels ranged from 52.8 to 129.0% for 117 compounds in LC-MS/MS. In GC-MS/MS, recoveries at three spiked levels ranged 30.6 to 129.0% for 129 compounds. It was observed that 114 compounds in LC-MS/MS and 127 compounds in GC-MS/MS were in an acceptable range for multiresidue analysis (70-130% recovery and ≤30% RSD). In conclusion, all pesticides except probenazole can be analyzed using this developed method including QuEChERS sample preparation and MS analysis. The result of this study will contribute to the improvement of the residual pesticide safety of the forage.