Abstract: A multi-residue determination method was developed for the simultaneous detection of 10 pesticide (dichlorvos, acephate, dimethoate, atrazine, acetochlor, malathion, fenthion, chlorpyrifos, cypermethrin, deltamethrin) residues in forage grass, using QuEChERS method and gas chromatography-tandem mass spectrometry (GC-MS/MS). The homogenized sample was dispersed by sodium chloride solution. Then the analytes were extracted with acetonitrile. Dispersive solid phase exaction (DSPE) was carried out for the analytes purification, using anhydrous magnesium sulfate, primary secondary amine (PSA), C₁₈ and graphitized carbon black (GCB). Ethyl acetate was used as solvent substitution after solvent evaporation under nitrogen. The 10 pesticide residues were then analyzed by GC-MS/MS using capillary column HB-5MS (30 m×250 μm, 0.25 μm) and multiple reaction monitoring (MRM). All the correlation coefficients of calibration curves were over 0.99 in the linear concentration ranged from 1 to 200 μg/L. The limits of detection (LODs) were 0.001 5-0.015 mg/kg and the limits of quantitation (LOQs) were 0.005-0.05 mg/kg. The average recoveries of the 10 pesticides at 3 spiked concentration level, 0.05, 0.2 and 1.0 mg/kg, varied from 75% to 110%, with the relative standard deviations (RSDs) ranged from 1.7% to 11.6%. This method was utilized to detect the real samples in Shandong. 100 batches of forage grass were selected, and residues of 8 pesticides in those samples were detected. According to MRLs from China, USA and Japan, the residues in the samples were safe. The QuEChERS-GC-MS/MS method was established as a simple, rapid, cost-effective, sensitive and accurate method to detect the above 10 pesticide residues in forage grass.