This paper addresses a platform-based design for a bio-inspired amphibious robot well-suited for multi-mode motion both on ground and under water. It concerns mechanical design, hardware implementation, software design, as well as ADAMS-based modeling. By introducing well-established software and hardware architectures, an ARM+uC/OS-II centered embedded control system is formed. With the sensor subsystem processing the gathered robotic and environmental information effectively, different motion modes will be adopted under dynamically changing environments. Preliminary testing partly verifies the feasibility of the platform-oriented, amphibious robotic prototype.