Abstract: Taking the injection-molding process of a cutting tool holder with magnetic inserts as a case study, this paper reported an investigation on the warpage defect occurring in injection-molded magnetic inserts by using acrylonitrile-butadiene-styrene copolymer (ABS) resin as a thermoplastic material and also proposed the resolution for this defect. A comparative analysis was conducted by means of Moldflow software for the influence factors derived from part structures, mould structures and process parameters.The results indicated that, through range analysis of process parameters and data analyses of product structures and gate locations, the warpage level could be improved by 15 % through optimizing the process parameters, improved by 53.7 % through optimizing the part structure, and improved by 76.5 % through optimizing the gate location.It was concluded that the optimization of gate location was the optimal method to diminish the warpage defect.