Abstract： Objective:To explore the expression level of serum lipoprotein a in patients with primary lung cancer bone metastasis, and provide new ideas and basis for the diagnosis and treatment of primary lung cancer bone metastasis.Method:400 patients with primary lung cancer who visited the Fifth Affiliated Hospital of Guangzhou Medical University between October 2017 and October 2022 were selected as the research subjects. Among them, 280 cases were in the primary lung cancer bone metastasis group, including 200 males and 80 females, with an age range of 28 to 85 years old; The remaining 120 cases were in the primary lung cancer group without bone metastasis, including 90 males and 30 females, with an age range of 29 to 88 years old. All patients with bone metastases underwent bone scanning and magnetic resonance imaging (MRI) examination. General clinical data of these patients were collected and the expression level of serum lipoprotein a in the plasma of the included patients were measured.Results:There was no statistically significant difference in gender distribution, smoking history, and alcohol consumption history between patients with and without bone metastasis in primary lung cancer (all P>0.05) . The expression level of serum lipoprotein a in patients with bone metastasis in primary lung cancer was significantly higher than that in patients without bone metastasis ( P<0.05) . Conclusion:The expression level of serum lipoprotein a in patients with primary lung cancer bone metastasis is significantly higher than that in the non bone metastasis group, which may provide new ideas and basis for the diagnosis and treatment of primary lung cancer bone metastasis.