Harmonia axyridis have become extremely popular through their extensive elytra and spot variation for many years. However, phenotypic polymorphism and striking visual phenotypes are not yet to be extensively studied. With growing attention to polymorphism of H. axyridis, it is imperative to study involved in genomic research in order to elucidate the molecular mechanisms underlying the diversity of elytra variation. To figure out suitable approach for analyzing genes of H. axyidis, we assessed RNAi as a tool for functional analysis. In order to demonstrate the utility of RNAi technique on H. axyridis, we conducted cDNA library screening to affirm silencing effect. We choose random genes from cDNA clones and the random genes were synthesized into dsRNA. After the injection of dsRNA into last instar larvae, we observed morphological defects or deaths. To investigate the effectiveness of knockdown in H. axyridis, we performed quantitative real time PCR on H. axyridis that appears the most distinctive features. These results provide that RNAi is highly applicable in H. axyridis and it will be useful for the gene functional analysis.