Abstract: 【Objective】This experiment was aimed to investigate the differences of semen quality and sperm DNA damage in Landrace boars with high and low reproductive performance,provide reference basis for screening out high fertility boars,so as to optimize artificial insemination ofpigs and improve the economic benefits of pig farms.【Method】Twelve French landrace boars were selected and divided into two groups of high and low reproductive performance by analyzing breeding data,with 6 pigs in each group. The boar semen quality parameters were determined by computer-aided sperm analysis(CASA) system. The sperm DNA fragmentation index(DFI) and reactive oxygen species(ROS) level were determined by flow cytometer.【Result】The average litter size and alive litter size of high fertility boars were extremely significantly higher than those of low fertility boars(P<0.01,the same below),but there was no significant difference in abnormal litter size and dead litter size between the two groups(P>0.05,the same below). The sperm progressive movement rate of high fertility boars was significantly higher than that of low fertility boars(P<0.05,the same below),and the sperm deformity rate was extremely significantly lower than that of low ones,but there was no significant difference between the two in the rate of proximal protoplasm drop,distal protoplasm drop and abnormal tail. Except that the curvilinear velocity(VCL) of spermatozoa of high fertility boars was significantly higher than that of low fertility boars,there was no significant difference in other motion parameters. The levels of sperm DFI and ROS in high fertility boars were extremely significantly lower than those in low fertility group. The correlation analysis between litter size and semen quality parameters of Landrace boars showed that litter size was highly negatively correlated with sperm DFI(r=-0.85),moderately negatively correlated with sperm deformity rate(r=-0.70) and sperm ROS level(r=-0.78),and the sperm deformity rate of Landrace boars was positively correlated with sperm DFI(r=0.63) and ROS level(r=0.62). Moreover,there was a highly positive correlation between sperm DFI and ROS levels(r=0.93).【Conclusion】Sperm DNA fragmentation is closely related to boar reproductive performance,sosperm DFI can provide an important reference for evaluating boar semen quality and reproductive performance. Therefore,the detection of sperm DFI during the selection of boar sperm collection can be used as a supplementary method for the evaluation of boar sperm quality,so as to improve the fertilization rate and the economic benefits of the pig farm in cooperation with artificial insemination technology,thus promoting the high-quality development of the pig industry.