Abstract: N-alkanes and polycyclic aromatic hydrocarbons serve as key molecular indicators for reconstructing marine paleoclimate, tracing organic matter sources, and evaluating anthropogenic pollution. Current literature still employs separate pretreatment and detection methods for these two substance categories. For co-extraction, highly polar mixed solvents such as chloroform-methanol or chloroform-acetone are typically used, resulting in numerous co-extracted impurities that reduce quantitative accuracy. This method utilizes a low-polarity n-hexane-acetone (4:1) mixture as the extraction solvent, which reduces co-extracted impurities and improves detection accuracy while ensuring the recovery of all components. By optimizing the gas chromatographic temperature program, complete baseline separation of 53 compounds including 34 n-alkanes, 16 polycyclic aromatic hydrocarbons (PAHs), and 3 PAH surrogates (naphthalene-D8, anthracene-D10, and p-terphenyl-D14) were achieved within 80 minutes.Methodological evaluation results indicate that 50 target compounds exhibit good linearity within the range of 10 ng/mL to 20 μg/mL, with correlation coefficients exceeding 0.999. The detection limits for n-alkanes range from 0.04 to 1.35 ng/g, while the quantification limits range from 0.16 to 5.40 ng/g. For polycyclic aromatic hydrocarbons, the detection limits ranged from 0.14 to 0.43 ng/g, with quantification limits from 0.56 to 1.72 ng/g. At three spiking levels (1×, 2×, and 8× the QL), recovery rates for target compounds ranged from 60% to 130%, with relative standard deviations (RSD) ranging from 0.22% to 7.04% (n = 6). The detection limits and quantification limits for both substance categories were below standard method requirements, and recovery rates met standard criteria. This work is applicable for the simultaneous extraction and detection of n-alkanes and polycyclic aromatic hydrocarbons in marine sediments.