研究了黄土高原油松、刺槐人工林对土壤的培肥效应。结果表明：油松、刺槐人工林能显著提高土壤肥力水平，降低土壤ｐＨ。１８龄油松１．２ｍ２及３３龄刺槐１．６ｍ２根区土壤断面的有机质、全氮、有效氮、有效钾、ＣＥＣ均值较无林对照分别提高５７．８％、６８．６％、１０９．３％、２８．９％、５４．４％及７４．３％、１２３．６％、２８５．３％、４２．４％、６３．７％，ｐＨ降低１４．４％及２．９％。油松、刺槐林对土壤的培肥效应符合深度模型ｙ＝Ａ＋Ｂｌｎｈ。 The effects of Pinus tabulaeformis and Robinia pseudoacacia plantation on soil fertility were studied. The results showed that Pinus tabulaeformis and Robinia pseudoacacia plantation could significantly increase soil fertility and decrease soil pH. The average values ​​of organic matter, total nitrogen, available nitrogen, available potassium and CEC in soil sections of 18m Pinus tabulaeformis 1.2m2 and 33m Robinia pseudoacacia 1.6m2 root zone increased by 57.8% and 68.6%, respectively, compared with no forest control. 3%, 28.9%, 54.4% and 74.3%, 123.6%, 285.3%, 42.4% and 63.7% respectively. The effects of Pinus tabulaeformis and Robinia pseudoacacia on soil fertility were in accordance with the depth model y = A + Blnh.