Abstract: Polyurea elastomer coated steel plates and coated fiber reinforced composite laminates were investigated on their penetration resistance and layers' mutual effect. Ballistic experiment of two polyurea coated substrates subjected to 3.3 g cubic fragments was conducted. Ballistic limits of three coating types of structures-uncoated, impact side coated and rear side coated-were obtained. Penetration resistance of different polyurea coated structures was analyzed with the deformation and failure characteristic. Experimental results indicate that the effect of polyurea coating on penetration resistance is related to energy absorption mechanism of each substrate;the forms of energy absorption of steel plates include partial deformation and shear plugging. Energy consumption of steel plates is hardly affected by coating. Polyurea coating can improve penetration resistance of coated steel plates and the effect of front-side coating is superior to that of back-side coating; back-side coating can inhibit the energy absorption of fiber plates and significantly reduce penetration resistance.