Objective?Objective To explore the correlation between prostatic hyperplasia and serum 25- hydroxyvitamin D level in elderly men. Methods?A retrospective study was conducted on the clinical data of 75 elderly male prostate patients admitted to Rizhao Hospital of Traditional Chinese Medicine from January 2019 to December 2020. The patients were divided into control group and study group according to their serum 25-hydroxyvitamin D level. There were 14 patients in control group (serum 25-hydroxyvitamin D level ＞ 20 ng/mL) and 61 patients in study group (serum 25-hydroxyvitamin D level ≤ 20 ng/mL),the general information, related biochemical indexes and insulin resistance index of all patients after admission were collected and analyzed. Results?Vitamin D deficiency was found in 81.33% of 75 patients;Logistic regression analysis showed that prostate volume (PV) was a protective factor for normal serum 25-hydroxyvitamin D level, while insulin resistance index (HOMA-IR) was a risk factor for normal serum 25-hydroxyvitamin D level.Conclusion?Low levels of serum 25- hydroxyvitamin D may be associated with prostatic hyperplasia in older men, PV and HOMA-IR were the influencing factors of 25-hydroxyvitamin D deficiency in patients with BPH.