The diffusion behavior of benzotriazole and sodium benzoate in low-density polyethylene of volatile corrosion inhibitor film was studied via a constant temperature and humidity chamber at different temperature, as well as molecular dynamics simulations at the molecular level, comparatively. The effect of the shape and size of the corrosion inhibitor molecules, temperature, free volume of the diffusion system, self-diffusion in low density polyethylene, and the interaction energy between the corrosion inhibitor molecules, and the low-density polyethylene on the diffusion rate of the corrosion inhibitors was analyzed. The results show that the diffusion rate of benzotriazole and sodium benzoate in the low-density polyethylene increased with increasing temperature, moreover, the diffusion rate of the single benzotriazole was less than that of sodium benzoate. When co-existence of benzotriazole and sodium benzoate in the polyethylene, their diffusion rates lowered in contrast to that the polyethylene containing only one inhibitor either benzotriazole or sodium benzoate, and which decreased with the increasing sodium benzoate content. The interaction between the corrosion inhibitor molecules and the interaction between the corrosion inhibitor and the diffusion system were important factors affecting the diffusion of the corrosion inhibitor, and the diffusion of sodium benzoate may have an inhibitory effect on the diffusion of benzotriazole. The measured and simulated diffusion coefficients of benzotriazole in low-density polyethylene show the same variation trend, but their values differ by one order of magnitude. Even so, the result can still provide a technical reference for release control and formulation of corrosion inhibitors.