The replication accuracy of ultra-high molecular weight polyethylene (UHMWPE) was investigated by using injection molding (IM) and injection compression molding (ICM). The mold insert was fabricated by using a stainless-steel etching method. Both the injection molded part and the injection compression molded part were observed under a microscope to compare the quality and accuracy of the replication. A high performance surface profiler was used to measure the microstructure profile. For the mold insert, the injection molded parts and injection compression molded parts were measured. The experimental results show that the UHMWPE can fill in microcavities by using IM and ICM technology. The height and shape of microstructure were influenced by the IM process parameters. For an injection molded part, the injection velocity was the most significant factor. This study also revealed that the ICM method was a more stable microstructure processing method than that of the IM. However, for better replication accuracy, both the IM and ICM processes require parametric optimization.