Abstract: According to the requirement for the application of micro-injection compression molding technology in the field of thin-walled microscale plastic parts with flexible substrates, this paper reported a study on the preparation and process technology of microneedle arrays with a flexible substrate through micro-injection compression molding. On the basis of the design of laminated microneedle pyramid mold, polypropylene (PP) was used as an experimental material to explore the effect of process parameters on the molding quality of microneedle arrays. The experimental results indicated that the optimal height for microneedles was 329 μm. The injection speed, melt temperature and secondary clamping pressure were found to have a significant influence on the height of microneedles through a range analysis. A molecular orientation stress model was used to explain the trend of the curve from a microscopic viewpoint. The analysis of variance indicated that the injection rate of molding was taken as the greatest contribution rate, reaching 25.3 %.