Quantitative analysis of target elements Mg, Ti, Ni, and Cr in standard oil was performed using substrate-assisted laser-induced breakdown spectroscopy. Mg II 279.55 nm, Ti I 334.94 nm, Ni I 352.45 nm, and Cr I 425.44 nm were selected as the spectral lines of the target elements in the quantitative analysis. The effects of sample pretreatment time, average sample oil film thickness, detection delay, and energy of laser pulse on the spectral signal intensity and signal-to-background ratio of Mg, Ti, Ni, and Cr were investigated. Under the optimal experimental conditions, the standard curve calibration model was established using six standard oil samples. The limits of detection of Mg, Ti, Ni, and Cr were 3.10, 8.17, 18.79, and 6.10 μg·g -1, respectively. The mass ratios of Mg, Ti, Ni, and Cr in other five standard oil samples were predicted by the calibration curve, and the relative errors were 7.43%, 8.91%, 13.66%, and 10.40%, respectively.