Abstract: Hepatocellular carcinoma (HCC) has a high incidence in China and is often difficult to detect early. Developing diagnostic reagents that can specifically target and trace HCC cells is crucial for early diagnosis and treatment of cancer. In this study, a novel glypican-3 (GPC3)-targeted theranostic biomaterial was developed. Using bovine serum albumin (BSA) as a carrier, GPC3-targeting peptides were modified onto the protein via a simple Michael addition reaction between maleimide and cysteine residues of the protein. Subsequently, chlorin e6 (Ce6), a photosensitizer with fluorescent and photodynamic therapy properties, was loaded into the peptide-modified BSA through host-guest self-assembly, constructing a HCC-specific targeted theranostic biomaterial. The results showed that the theranostic material exhibited significantly stronger fluorescence intensity in GPC3-highly expressed HepG2 cells than in low-expression cells (P<0.001). Under 630 nm light irradiation, the viability of HepG2 cells treated with the biomaterial was significantly lower than that of control PLC cells at the same concentration (P<0.05), confirming the targeted theranostic effect of the biomaterial. This work provides a novel targeting delivery material for the early diagnosis and treatment of HCC cells.