Objective: To explore the mechanisms of Qianjing Decoction in the treatment of oligoasthenospermia (OAS)., Methods: We randomly divided 100 SPF male rats into five groups of equal number: normal, model, Huangjingzanyu, levocarnitine, and Qiangjing. OAS models were established in the animals followed by intragastrical administration of normal saline, ornidazole, Huangjingzanyu Capsules (200 mg per kg body weight per day), levocarnitine (100 mg per kg body weight per day), and Qianjing Decoction (10 g per kg body weight per day), respectively, qd, for 4 successive weeks. Then, we detected the concentration and motility of the epididymal sperm, obtained the contents of superoxide dismutase (SOD), malonaldehyde (MDA), glutathione peroxidase (GSH-Px), lactate dehydrogenase (LDH), α-glucosidase, and fructose in the epididymis, and determined the mRNA expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and succinate dehydrogenase (SDH) in the epididymal tissue of the rats by real-time PCR., Results: The concentration and motility of the epididymal sperm in the model, Huangjingzanyu, levocarnitine, and Qianging groups were (35.34 ± 4.22) x 10(6)/ml and (40.04 ± 7.05)%, (48.12 ± 5.56) x 10(6)/ml and (62.46 ± 7.12)%, (47.14 ± 4.87) x 10(6)/ml and (63.23 ± 6.34)%, and (50.25 ± 5.08) x 10(6)/ml and (66.34 ± 7.58)%, respectively, all significantly lower than in the normal group ([53.05 ± 4.55] x 10(6)/ml and [70.20 ± 8.54]%) (P < 0.05), but remarkably higher in the Huangjingzanyu, levocarnitine, and Qiangjing groups than in the model rats (P < 0.05). Compared with the thinned epididymal lumen walls, decreased sperm count, and disorderly and loose arrangement of the lumens in the OAS models, the rats in the Huangjingzanyu, levocarnitine, and Qiangjing groups showed evidently thicker epididymal lumen walls, with the lumens full of sperm cells and arranged regularly and compactly, similar to those of the normal rats. The levels of SOD and GSH-Px were significantly lower but that of MDA markedly higher in the model rats ([84.12 ± 23.25], [10.56 ± 3.02], and [14.04 ± 2.06] nmol/mg) than in the normal group ([110.04 ± 19.56], [17.25 ± 3.56], and [8.87 ± 1.35] nmol/mg) (P < 0.05), while the former two indexes remarkably higher and the latter one significantly lower in the animals treated with Qiangjing Decoction ([120.56 ± 23.68], [16.34 ± 3.12], and [8.45 ± 1.56] nmol/mg), Huangjingzanyu Capsules ([115.34 ± 21.35], [15.23 ± 3.67], and [8.33 ± 1.54] nmol/mg), and levocarnitine ([116.67 ± 22.67], [15.35 ± 3.45], and [8.05 ± 1.78] nmol/mg) than in the models (P < 0.05). The levels of fructose, LDH and α-glucosidase were decreased markedly in the OAS models ([100.22 ± 12.12] mg/[ ml x g], [322 ± 46.13] U/[ ml x g], and [10.48 ± 2.33] U/[ml x g]) as compared with the normal rats ([128.12 ± 13.45] mg/[ml x g], [428 ± 35.12] U/[ml x g], and [15.34 ± 3.12] U/[ ml x g]) (P < 0.05), remarkably higher in the rats treated with Qiangjing ([130.23 ± 13.67] mg/[ml x g] [455 ± 51.50] U/[ml x g], and [18.56 ± 4.67] U/[ml x g]), Huangjingzanyu ([124.16 ± 14.02] mg/[ml x g], [ 419 ± 43.14] U/[ml x g], and [17.64 ± 4.08] U/[ml x g]), and levocarnitine ([123.34 ± 14.02] mg/[ml x g], [430 ± 31.80] U/ [ml x g], and [16.85 ± 5.55] U/[ml x g]) than in the models (P < 0.05). The Nrf2 mRNA expression was significantly reduced in the models as compared with the normal rats (P < 0.05) but remarkably increased in the Huangingzanyu, Qiangjing and levocarnitine groups as compared with the model and normal animals (P < 0.05). The SDH mRNA expression was significantly lower in the model than in the normal rats (P < 0.05) but markedly elevated in the Huangjingzanyu, Qiangjing and levocarnitine groups as compared with the model and normal animals (P < 0.05), remarkably higher in the Qiangjing than in the Huangjingzanyu group (P < 0.05)., Conclusion: Ornidazole induces OAS in rats, which is closely associated with excessive oxidation and energy metabolism dysfunction. Qiangjing Decoction can improve and even reverse ornidazole-induced OAS in rats as well as improve the ultrastructure of their testicular and epididymal tissues. Antioxidation and improvement of energy metabolism are probably the action mechanisms of Qiangjing Decoction in the treatment of OAS.