The invention provides a preparation method for a solvent-resisting, high-toughness and flame-retardant PC (polycarbonate)/ABS (acrylonitrile butadiene styrene) compound. The method comprises the following steps: putting PC, a phosphorus-containing flame-retardant agent and an ABS-flexibilizer one-step material and transition metal complex into a high-speed mixer for mixing; and putting the mixture into a double-screw extruder for extruding, thereby acquiring the solvent-resisting, high-toughness and flame-retardant PC/ABS compound. The solvent-resisting, high-toughness and flame-retardant PC/ABS compound provided by the invention has the advantages that the one-step material is simple and is easily acquired; the preparation process is simple; the cost is low; a high-gloss, high-fluidity and high-toughness material is prepared; and the method can be widely applied to the industries of automobiles, refrigerators and TV sets.