In order to provide basic parameters for rustproof packaging of Cr-Mn alloy steel, the relationship of corrosion rate with environmental humidity and time was studied by experiment. The effects of several typical rust-proof packaging technologies were compared. The results showed that the antirust period of Cr-Mn alloy steel in natural environment is about 35 days; after the antirust period, the rust will appear and accelerate with increasing of temperature and humidity; the composition of rust inhibitor and antirust film is the best antirust packaging method. The research results were applied to the rust-proof packaging of a Cr-Mn alloy steel products, and the rust-proof effect was verified through acceleration test. The results showed that the rust-proof packaging can ensure product to have no corrosion phenomenon at least one year.