A mobile device includes a mobile platform, a spray generating assembly, an ultraviolet light-emitting module, a scanning module and a controlling module. The spray generating assembly is to generate a disinfecting and sterilizing spray for a spraying, disinfecting and sterilizing operation in the working area. The ultraviolet light-emitting module is configured to generate ultraviolet beams for performing a radiating, disinfecting and sterilizing operation onto a ground surface of the working area. The scanning module defined with an entire scan range is configured to generate a warning signal upon a human in the entire scan range. The controlling module, electrically connected with the scanning module and the spray generating assembly, is configured to control the spray generating assembly to stop generating the disinfecting and sterilizing sprays upon receiving the warning signal, so as to prevent the human from inhaling excessive sprays.