Abstract: A method for determination of ferrum, manganese, lead and slicon in lightweight oil by inductively coupled plasma-atomic emission spectrometry (ICP-AES) combined with organic sampling system was established. Lightweight oil of 5.000 0 g was placed in plastic bottle, and internal standard solution of 45 g was added to prepare lightweight oil solution for test. Internal standard method was used for quantitative analysis by organic sampling system. In ICP-AES analysis, analytical spectral lines of ferrum, manganese, lead and silicon were 238.204, 257.610, 220.353 nm and 251.611 nm, respectively, with radio frequency power of 1 100-1 300 W, auxiliary gas flow rate of 2.0 L·min^-1, atomization gas flow rate of 0.30 L·min^-1, cooling gas flow rate of 16 L·min^-1, oxygen flow rate of 20-35 mL·min^-1. It was showed that linear ranges of calibration curves of ferrum, manganese, lead and silicon were within 5.0 mg·kg^-1, and detection limits (2.821s) were less than 0.01 mg·kg^-1. RSDs (n=8) of determined values of each analyted element on 0.2 mg·kg^-1 matrix matching mixed standard solution were less than 6.0% within 2 h. Matrix matching mixed standard solutions with mass fractions of 0.1, 0.2, 1.0 mg·kg^-1 were determined, and RSDs (n=6) of determined values for each analyted element were in the range of 2.6%-7.9%. Recovery test was made on substantial samples by standard addition method, giving results in the range of 97.7%-103%.