Nanoparticles have shown great promise for improving the efficacy of nucleic acid drugs that lack permeability and bioavailability needed for reaching their intracellular site of action. The pharmacokinetics of the nucleic acid nanomedicines contributes greatly to their pharmacodynamic and toxicity characteristics. The pharmacokinetics of nanomedicines is determined by their physiochemical properties, such as particle size, shape, surface charge, and surface modifications. This review presented the pharmacokinetic and pharmacodynamic perspectives of nucleic acid nanomedicines. The cellular trafficking of the nucleic acid nanomedicines after cellular uptake is also discussed. In addition, the review puts forward potential strategies for circumventing biological barriers to delivering and releasing nucleic acid drugs into their intracellular site of action, and perspectives in this rapidly evolving field.