C-type lectins (CTLs) are an important class of pattern-recognition receptors (PRRs) involved in invertebrate innate immunity. Herein, a perlucin-like protein (PLP) from Pinctada fucata martensii was cloned and characterized and designated as PmPLP. The immune-related activities of the recombinant protein (rPmPLP) were systematically evaluated. Sequence analysis revealed that PmPLP encodes 161 amino acids, containing a typical C-type lectin-like domain (CTLD) with "QPD" and "WND" carbohydrate-recognition motifs. Bacterial growth inhibition assays demonstrated that rPmPLP significantly suppresses the growth of four Gram-positive bacteria, four Gram-negative bacteria, and two fungi, indicating broad-spectrum antimicrobial activity. Scanning electron microscopy (SEM) observations further revealed that rPmPLP induces morphological damage to bacterial structures, with species-dependent morphological alterations. This protein specifically binds to peptidoglycan (PGN) and Poly(I:C), but not to lipopolysaccharide (LPS). Moreover, rPmPLP exhibited binding activity to both Gram-negative (Aeromonas hydrophila, Pseudomonas aeruginosa) and Gram-positive (Streptococcus agalactiae, Micrococcus luteus) bacteria, and could agglutinate various bacteria, including Escherichia coli, P. aeruginosa, A. hydrophila, Staphylococcus aureus, M. luteus, and Bacillus subtilis. In conclusion, PmPLP possesses the structural characteristics of a typical C-type lectin, and its recombinant protein, rPmPLP, recognizes, binds to, and agglutinates various microorganisms while displaying direct antimicrobial activity. This study provides new evidence on the innate immune mechanisms of P. f. martensii and offers experimental data supporting antimicrobial immune mechanisms in shellfish.