According to the superiority performance, the applications of engineering plastics tend to be widely used day by day in the field of railway transport. The research of locomotive-bearing retainer is an important technology that should be resolved proposed by the Ministry of Railways’ report on the outline of the Eleventh Five-Year Plan. In this paper, the characteristics of each process of the injection molding in the different stage, the main technology parameters, and the influence of the primary process parameters on the part manufacture quality were systematically analyzed. And the modern injecting forming software and new technology were applied to analyze the injecting forming technology, to design the mould structure, to forecast the possible defects and breakdown in the process of injecting forming with the thematically design and the CAE technology. The study results can be extended to the design of other similar parts, which has very strong engineering applications significance.