We report on the antibacterial and cytocom-\patibility properties of a bio-based electrospun polyhydroxyalkanoate (PHA) nanofiber modified with Black Soldier Fly (BSF) pupa shell. A 5-50 mu m chitosan powder (CSP) was made by grinding BSF pupa shell in water, acid, alkali. CSP was combined with PHA in an electrospinning machine using a biaxial feed method and manufactured into a 50-500 nm antibacterial nanofiber. We studied the morphology, mechanical properties, water absorption, and antibacterial properties of the electrospun PHA/CSP nanofiber. To improve the fiber's compatibility and functionality, acrylic acid (AA) was grafted onto PHA. The resulting tensile properties and morphological characterizations indicated enhanced adhesion between CSP and PHA-g-AA nanofiber, as well as an improvement in its water resistance and tensile strength, compared with the PHA/CSP nanofiber. To study the cytocompatibility of the material, human foreskin fibroblasts were seeded onto the nanofiber specimens with 3.0 and 6.0 wt % CSP. Increasing the CSP content in PHA/CSP and PHA-g-AA/CSP nanofibers enhanced cell proliferation; additionally, the nanofibers with CSP showed strong inhibition of bacteria. The enhanced antibacterial and biodegradable properties of PHA-g-AA/CSP and PHA/CSP nanofibers demonstrate their potential for biomedical material applications.