A method for the determination of Al,Si,V in residual fuel oil was developed by DUO-ICP-AES with microwave ashing technology.The operative conditions of DUO-ICP-AES were optimized.Under the optimal conditions,the calibration curve was linear in the range of 0-250 mg/L with correlation coefficients(r) of 0999 70-0999 99.The detection limits ranged from 0005 mg/L to 0050 mg/L.The spiked recoveries were in the range of 88%-97% with RSDs of 10%-35%.The method was simple and rapid,and could be applied in the routine analysis of Al,Si,V in residual fuel oil.