Abstract: This review described the potential health threats to the cardiovascular system from micro-nano plastics (MNPs) and their multifaceted toxicity mechanisms. The article reviewed the environmental distribution of MNPs, exposure pathways, and their toxic effects on the cardiovascular system, and summarized the specific mechanisms of MNPs involving oxidative stress, inflammatory response, mitochondrial damage, apoptosis, pyroptosis, and autophagy dysregulation. Meanwhile, the combined toxic effects of MNPs with other environmental pollutants (e.g., heavy metals and polycyclic aromatic hydrocarbons), including synergistic, antagonistic, and dual effects, were analyzed, and the potential risks of MNPs as carriers of microorganisms and toxic chemicals were pointed out. The widespread presence of MNPs and their complex toxicity mechanisms may make them important triggers for cardiovascular diseases, but current research still suffers from unbalanced studies across environmental systems, incomplete understanding of plastic properties, and limited knowledge of long-term biological effects. Future research should focus on the long-term effects of MNPs, the joint toxicity mechanisms with other pollutants, and the differential effects across population subgroups. It is suggested to accelerate plastic recycling technology innovation, promote biodegradable materials, and optimize waste treatment process to mitigate the potential threat of MNPs pollution to human health. Through multidisciplinary collaboration and in-depth research, combining innovative concepts from toxicology, public health policy, and environmental science, it is expected to provide new methods and approaches for the prevention and treatment of cardiovascular diseases associated with MNPs.