<p>Amphibious mobile robots can replace humans in performing continuous tasks across diverse amphibious environments, enhancing operational efficiency and reducing risks. However, the complexity and variability of amphibious environments and the wide range of tasks present significant challenges in developing robots capable of amphibious operations. This study introduces a novel multi-modal amphibious robot named Amp-beetle, based on an integrated wheel-leg-propeller drive system. The design leverages the driving characteristics of wheels, legs, and propellers in various environments, enabling the robot to adapt to amphibious conditions and perform continuous operations across different terrains. By altering the configuration of the drive components and adjusting the leg rotation angles, Amp-beetle can freely switch between different movement modes and achieve vector propulsion underwater. Additionally, this paper investigates how the thrust generated by the integrated wheel-leg-propeller structure, along with shifts in the robot’s center of mass and buoyancy, affects the robot’s motion characteristics under different modes. The robot’s design was validated through theoretical analysis, prototype development, and various performance tests in simulated operational environments, demonstrating excellent balance and maneuverability.</p>