Young’s modulus is a fundamental physical quantity that characterizes the elastic properties of materials and is of great importance in physics teaching and engineering applications. In this study, an adjustable bending-beam device for measuring Young’s modulus was designed and fabricated based on 3D printing technology. The device has a modular structure, with adjustable support span, specimen interfaces, and loading configurations, allowing it to accommodate specimens with different cross-sectional shapes. To ensure measurement reliability, a complete measurement procedure and an uncertainty evaluation model were established. Measurements of an aluminum alloy beam yielded a Young’s modulus of 70.12(57)GPa, with a deviation of less than 1% from the reference value. Measurements of a non-standard material, spaghetti, gave a value of 4.540(50)GPa, further demonstrating the applicability of the device in open-ended experiments. In addition, students can use 3D printing to independently design beams with different cross-sectional shapes and investigate the influence of cross-sectional geometry on bending stiffness. In this way, the experiment can be extended from simple parameter measurement to an inquiry-based task involving design and analysis. This work provides a low-cost and flexible solution for university physics experiments and helps bridge physical principles with engineering practice.