An unmanned vehicle includes a vehicle body having an accommodating space, an arm assembly coupled to the vehicle body, and a floating member connected to a bottom surface of the vehicle body. The arm assembly includes a first rotating member, a second rotating member coupled to the first rotating member, and a propeller. The propeller includes a rotatable axle coupled to the second rotating member and extending along a rotating axis. The second rotating member can turn the propeller by rotating the rotatable axle about the rotating axis. The first rotating member can rotate and effect a movement of the second rotating member so as to selectively adjust the rotatable axle to align the rotating axis with a first axial direction and a second axial direction. The arm assembly can rotate relative to the vehicle body to selectively rotate into or out of the accommodating space.