Environmental light pollution adversely affects brain function, disturbing circadian rhythms and negatively impacting human health. Nanoplastics (NPs) pollution is pervasive in the human environment, and their minuscule size facilitates entry into the body, particularly invading brain and compromising its functionality. However, whether NPs infiltrate rhythm-regulated brain regions and disrupt circadian rhythms in organisms remains unclear. Our study demonstrates that exposure to NPs in mice perturbs normal circadian rhythms. Specifically, NPs invade the suprachiasmatic nucleus (SCN), affecting the circadian clock genes network and altering the regular oscillations of core clock genes. Exposure to NPs renders the intrinsic rhythms more susceptible to disruption by light pollution, resulting in more pronounced disorder to metabolism, immune regulation, and brain function. This work is the first to investigate the combined effects of ambient light pollution and NPs pollution on mammalian health, and our findings suggest that NPs amplify the health impacts of light pollution. These findings also highlight that efforts to mitigate human health risks from environmental pollutants should begin to consider the synergistic effects of various classes of pollutants.