Objective：This study aims to investigate the relationship between chemokine C-X-C motif ligand 4（CXCL4） and gender differences in lung tissues of neonatal mice with hyperoxia-induced lung injury. Methods：Thirty-two mouse pups（16 animals per sex），were randomly and equally assigned to four groups：Hyperoxia-male group，Hyperoxia-female group，Room air-male group and Room air-female group，with 8 mice in each group. The mice in air group were exposed to room air（FiO2=21%）and those in hyperoxia group were exposed to hyperoxia（FiO2 ≥ 95%）for 7 days. All animals were sacrificed and lung tissues were excised for analysis via histological staining，tandem mass tags（TMT）technology and immunofluorescence staining. The levels of CXCL4 in tissue homogenates were measured. Results：The mouse pups exposed to hyperoxia had significant reductions in the degree of alveolarization，and radial alveolar count（RAC） in lung tissues（P < 0.001） was significantly decreased in hyperoxia-exposed animals and was decreased to a larger extent in males compared with females（P < 0.01）. Under hyperoxia intervention，CXCL4 upregulated was exclusively differentially regulated in hyperoxia exposed neonatal male mice compared to room air controls. M4 macrophage（MMP7+ S100A8+） infiltration was higher in male mice following postnatal hyperoxia exposure. Conclusion：These findings highlight sex-specific differences in hyperoxic lung injury，and male neonatal mice are more susceptible to hyperoxia-mediated lung injury and display larger arrest in lung alveolarization，which suggests the changes in M4 macrophages induced by CXCL4 may play a crucial role in sexual differences in neonatal hyperoxic lung injury.