The mantis shrimps are the only animal species known to science that can recognize circularly polarized light (CPL). Here we explored the morphological and molecular mechanisms of CPL recognition in Oratosquilla oratoria, a typical species of mantis shrimps. Through multilayer microscopy, we discovered the cross-arranged microvilli and the oval distal rhabdom to be the critical structures for CPL recognition. Based on the specific expression patterns of vision-related functional genes and proteins, we suggest that the order of light utilization by O. oratoria compound eye was first natural light, then left-rotation CPL (LCPL), linearly polarized light, right-rotation CPL (RCPL) and dark. Meanwhile, we found that the expression levels of vision-related functional genes and proteins in O. oratoria compound eye under RCPL were not significantly different from those in DL, and thus provide additional evidence that mantis shrimp can only recognize LCPL. Furthermore, the recognition of LCPL is likely facilitated by the differential expression of opsin and microvilli - related functional genes and proteins (arrestin and sodium-coupled neutral amino acid transporter). In conclusion, this study systematically illustrated for the first time how O. oratoria compound eye recognizes CPL, and it can improve the visual ecological theory behind polarized light recognition.