The present invention relates to an easily-plated PC/ABS alloy and its preparation method. The PC/ABS alloy includes following components: 30-70 parts by weight (pbw) of PC resin, 15-65 pbw of ABS resin, 5-10 pbw of PEO resin, 0.1-1 pbw of antioxidant, and 0.1-1 pbw of lubricant. For preparation, blending the PC resin, ABS resin, PEO resin, antioxidant and lubricant in a mixer; and putting a mixture in a twin-screw extruder for granulation, thus producing easily-plated PC/ABS alloy. The method is simple and practicable. PEO resin makes PC/ABS surface have the property of hydrophilicity, which makes the etching solution easier to wet the surface when under etching, so that the etching becomes much easier. The binding force of hydrophilic group on the surface of PEO to the metal is strong. The binding force of PC/ABS alloy material is improved due to the combination between the chemical bond and physical force.