由于前列腺特异性抗原（ＰＳＡ）在前列腺良恶性疾病诊断鉴别中存在一定误差率，故改用前列腺特异性抗原密度（ＰＳＡＤ）对３８例前列腺病患者进行研究，其中前列腺癌１１例，前列腺增生２７例。运用核磁共振（ＭＲＩ）测量前列腺长、宽、高，借助公式：体积＝长×宽×高×０．５计算出前列腺体积，则ＰＳＡＤ＝ＰＳＡ／Ｖ。研究结果表明：前列腺肥大ＰＳＡＤ平均值为０．０５５，前列腺癌ＰＳＡＤ平均值为１．１４４，前列腺增生组中ＰＳＡＤ最大值未超过０．２３，即使超过０．１５的仅２例。在总共１２例ＰＳＡＤ大于０．１５的患者中，前列腺癌占了１０例，而前列腺肥大仅２例。而ＰＳＡＤ小于０．１的范围中前列腺增生有２２例，而前列腺癌却无一例，由此可见ＰＳＡＤ可作为前列腺良恶性疾病鉴别诊断的有效指标之一。 Prostate-specific antigen (PSA) in the diagnosis of benign and malignant diseases there is a certain error rate, so the use of prostate-specific antigen density (PSAD) 38 cases of prostate disease in patients with prostate cancer in 11 cases, benign prostatic hyperplasia 27 example. Prostate length, width, and height were measured by nuclear magnetic resonance (MRI). Prostate volume was calculated using the formula: volume = length × width × height × 0.5, and PSAD = PSA / V. The results showed that the average value of PSAD in prostatic hypertrophy was 0.055, the average value of PSAD in prostate cancer was 1.144, and the maximum value of PSAD in prostatic hyperplasia group did not exceed 0.23, even though only 2 cases exceeded 0.15. Of a total of 12 patients with PSAD greater than 0.15, prostate cancer accounted for 10 and prostatic hypertrophy was only 2. PSAD is less than 0.1 in the range of 22 cases of benign prostatic hyperplasia, while there is no case of prostate cancer, which shows that PSAD can be used as a differential diagnosis of benign and malignant prostatic diseases, one of the effective indicators.