The three-layer-core-shell structure crosslinked styrene-acrylate emulsion containing glycidyl group, carboxyl group and amino group is synthesized. The effects of the thickness of mid-layer, the functionalmonomers amount on the properties of the emulsion and its film are investigated. It is found that the emulsion and its film has the best performance when the mid-layer amount is 50% of core and shell layers by weigh,t and GMA /MAA /DMAEMA amount is 3% /1.5% /3% of the total amount of each layer by weight respectively. The resulted coating film has better ant irust property, compared with conventional styreneacrylate emulsion. It was no rusting, no blistering, no peeling- off and no cracking after NaCl solution( 3% ) test for 624 hours.