Objective To explore the relationship between sperm DNA fragmentation index(DFI) and sperm quality, as well as in vitro fertilization-embryo transfer (IVF-ET) preganancy outcomes in middle-aged men. Methods   A total of 180 semen specimens from males aged over 38 years who received comventional IVF-ET treatment were collected and divided into two groups(<30% and ≥30%) based on the DIF threshold. Main measures result including: normal semen parameters, hormone levels, DFI, fertilization rate, good quality embryo rate and pregnancy rate. Results  DFI was closely related to male follicle-stimulating hormone（FSH）, sperm motility，morphology, and the sperm vitality decreased with increasing DFI level (P<0.05). When DFI≥30%, the rate of high-quality embryos decreased (P<0.05), but there was no significant difference in the pregnancy rate (P>0.05). Conclusion DFI can serve as an important indicator for routine analysis of semen in middle-aged men. DFI affects the rate of high-quality embryos, but it is not related to the clinical pregnancy outcome of assistant reproduction technology (ART).