Abstract: Succeis has been made through actual test and application in patching steel oil tanks untorched by means of brushing elastic polyurethane coating. The patching coat consists of the primary layer made of polyether polyurethane and the surface layer made of elastic polyurethane. The adhesive force of the primary and surface layers are stren gthed by adding a ransition layer.Attention, however, ahould be paid to storage of the materials and their respective effective datc, being on guard against any mixture of such elements as alkali, urethane, aleohol, water and soon. Tools must be tidy and clean, and fire and explosion be guarded a gainst on construction site.