Decreased sperm quality was caused by oxidative stress in semen from patients with leucocytospermia. Curcumin is a traditional Chinese herbal monomer extracted from Zingiberaceae turmeric and zedoary turmeric and has antioxidative and anti-inflammatory effects. This study aimed to investigate the effects and specific molecular mechanisms of curcumin on sperm quality in patients diagnosed with leucocytospermia. Forty cases of semen samples were collected from patients with leucocytospermia and 35 cases from normal fertile male. Computer-assisted semen analysis (CASA) was used to detect sperm motility after curcumin incubation. ELISA was used to measure the changes in H2O2, sperm mitochondrial DNA (mtDNA), cytochrome B (Cyt B) and NADH dehydrogenase 5 (NADH5) contents before and after curcumin treatment. The results indicate that curcumin can significantly improve sperm motility from the patients with leucocytospermia. After curcumin treatment, the level of the H2O2 was significantly decreased in the supernatant of curcumin-incubated spermatozoa from leucocytospermic patients. The content of mtDNA was significantly decreased, while the content of Cyt B and NADH5 in spermatozoa was significantly increased. In conclusion, curcumin can significantly improve sperm motility of leucocytospermic patients, against the oxidative damage induced by H2O2. Therefore, curcumin may play a role in mitigating the H2O2-induced injury to sperm.