Abstract: In response to prominent issues such as high noise and rotor airflow interference of unmanned aerial vehicles, as well as difficulty in cross domain control of ground mobile robots in close-range reconnaissance missions, a land-air amphibious robot is proposed. The robot has multiple modes such as flight mode and land driving mode. Through air flight, rapid arrival can be achieved, while low-noise close-range reconnaissance can be achieved by land travel. A lightweight transformable arm self-locking mechanism is designed, which ensures that the rotating arm is in a safe locked state without additional mechanical devices during flight, and maintains its state based on position errors during travel. The robot ability to pass through narrow spaces is improved. And then a structured body feathering mechanism is proposed, by which the blades can automatically return to centre, effectively solving the problems of electronic propeller, such as shaking, heating, and the loss of motor efficiency. A control strategy utilizing finite state machine based on lightweight laser sensing array and visual sensor is put forward. Stable control of aerial flight and ground travel, as well as state switching control of ground to air deformation and air to ground deformation are achieved. A prototype of land-air amphibious robot is manufactured, with a range ratio of over 6 and a close-range noise reduction from 70 dB in air to 52 dB on the ground. Finally, the verification in typical application environments such as wild grassland, rugged terrain, water wading roads, and indoor buildings are conducted. The land-air amphibious transformable robot can be applied to multi-dimensional reconnaissance and silent infiltration in complex multi-domain scenes.