Matrix proteins play a crucial role in regulating the formation of inorganic minerals. In order to investigate the effect of matrix proteins in Hyriopsis cumingii on shell biomineralization, this study isolated a new matrix protein gene cysrichin-F from H.cumingii, and further explored its biological function using techniques such as in situ hybridization, shell-breaking repair and RNA interference （RNAi）. The results showed that the full length of cysrichin-F sequence was 592 bp, and the open reading frame （ORF） region was 42-389 bp, encoding a total of 115 amino acids. The protein encoded by this gene has a theoretical molecular weight of 12.895 ku and a theoretical isoelectric point of 8.65, making it an alkaline protein. The front 23 amino acids of CYSRICHIN-F are signal peptides. Quantitative Real-time PCR （qRT-PCR） detection revealed that the expression level of this gene in the mantle was relatively high compared to other tissues. Through in situ hybridization and shell-breaking repair techniques, it was found that cysrichin-F was involved in the formation of the cuticle and prismatic layers of shells. After interference with this gene, the structure of the shell prismatic layer would be disrupted, ultimately resulting in an irregular shape of the shell prismatic layer. This study showed that cysrichin-F was involved in the biomineralization process of the cuticle and prism layers of shells. The results of the study can help to elucidate the molecular mechanism of the biomineralization in H.cumingii, and provide a theoretical basis for the role of matrix proteins in the formation of shells in H.cumingii.