Starch is a competitive bio-based feedstock for 3D printing ink fabrication. Herein, high-amylose corn starch was chemically modified via a two-step process involving an EMPO-NaBr-NaClO system and NaIO4 modification to prepare dual aldehyde-carboxylated starch (DACA). Composite 3D printing inks based on corn starch and DACA were formulated to fabricate antibacterial and preservative packaging boxes. The impacts of DACA on the printing fidelity, structural stability and mechanical performance of 3D-printed constructs were systematically evaluated, and their preservation functionality was further evalatued via a room-temperature blueberry storage tests. Results showed that the aldehyde content of DACA positively correlated with the oxidation degree. The ink with 17.5 wt.% corn starch exhibited optimal rheological and extrudability properties, enabling high-fidelity printing of solid and hollow structures with the best dimensional accuracy. In addition, with increased aldehyde content in DACA, the adhesion of printed samples decreased initially and then increased, while elasticity followed an opposite trend. DACA1 group achieved the minimum adhesion (24.37g) and maximum elasticity (0.47 mm). Owing to intermolecular covalent cross-linking, the cohesion of the 3D printed samples showed a decrease-increase-decrease pattern peaking at 0.37 in DACA2 group. Preservation experiment verified that both DACA and carboxylated starch (CA) significantly suppressed mold proliferation and tissue shriveling of blueberries, extending their shelf life to 10 days at room temperature. This work established a reliable strategy for the design and fabrication of tunable, high-performance 3D-printable antibacterial starch materials, which presented promising prospects for sustainable food preservation applications.