Waterborne polyurethane（WPU）latex was prepared with toluene-2,4-diiso-cyanate(TDI),polyether (DL-400,TMN-450) and 2,2-bis-(hydroxymethyl)-propionic acid (DMPA), and characterized by FTIR. Two kinds of methods, depositing WPU latex by adding 10% alum solution and latex polymerization were used to coat RDX.SEM results indicat that RDX is coated the best with 1% WPU coating content in destroying latex way; while RDX is coated worst by method of latex polymerization. Special height H₅₀ of RDX coated with WPU was determined by impact sensitivity test. And result indicate that H₅₀ of RDX before coating is 22.3 cm; that H₅₀ of RDX coated with 1% WPU in destroying latex way is 82.2 cm; that H₅₀ of RDX coated with 1% WPU by method of latex polymerization is 59.0 cm. Conclusion will be drawn through experiments that coating RDX by method of polymerization-depositing WPU latex can effectively improve the property of its sensitization, and increase the value of H₅₀, whose effects are predominant to that of polymerization.