Objective To analyze the relationship between lipoprotein-associated phospholipase A2 (Lp-PLA2) and intracranial arterial atherosclerotic plaques in order to investigate whether Lp-PLA2 can be a clinical marker for predicting the properties of the plaques for the elderly with stroke. Methods A total of 184 elderly patients with ischemic stroke diagnosed in our hospital from January 2017 to December 2019 were enrolled in this study. According to the results of head and neck CT angiography (CTA), 102 of them with moderate or severe middle cerebral artery or basilar artery stenosis (≥50%) were assigned into the experimental group, and the other 82 with normal CTA results into the control group. High-resolution MRI (HRMRI) examination was performed for the patients from the experimental group, and then they were divided into unstable plaque subgroup (n=52) and stable plaque group (n=50). Based on whether the target blood vessel of the plaque source was a responsible blood vessel for neurological symptoms, they were also assigned into responsible vascular subgroup (n=48) and non-responsible vascular subgroup (n=54). The general clinical data of all patients were collected, and the serum Lp-PLA2 level was measured by enzyme-linked immunosorbent assay (ELISA). SPSS statistics 20.0 was used for statistical analysis. Data comparison between two groups was perfomed using t test or χ² test depending on data type. Results The Lp-PLA2 level was significantly higher in the experimental group than the control group [(198.1±59.85) vs (130.22±59.35) ng/ml, P<0.05], and in the unstable plaque subgroup than the stable plaque subgroup [(227.32±45.89) vs (172.29±47.97) ng/ml, P<0.05]. But there was no statistical difference in the level between the responsible vascular subgroup and non-responsible vascular subgroup [(208.27±36.58) vs (211.54±57.18) ng/ml, P>0.05]. In the patients from the responsible vascular subgroup, no obvious difference was seen in the level between those with stable and those with unstable plaques [(210.92±54.01) vs (212.67±91.06) ng/ml, P>0.05]. Similar result was observed in the patients with stable and those with unstable plaques from the non-responsible vascular subgroup [(207.58±65.23) vs (209.36±50.36) ng/ml, P>0.05]. Conclusion Based on the characteristics of intracranial atherosclerotic plaques identified by HRMRI, serum Lp-PLA2 level is closely associated with the stability and vulnerability of the plaques, and may be regarded as an important marker in assessment of the stability and vulnerability of plaques in the future.